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Press 'OK' to continue. principles of meteorological doppler radar dynamic scanning motivation for this lesson what is dynamic scanning? allow forecasters to customize radar scans to meet their needs “right choice” mindset can cause issues research on dynamic scanning options is limited: kingfield and french (2022) cho et al. (2022) need to first understand the options then we can get into the applications goal: focus on tradeoffs, not “best choice” kingfield and french (2022) dynamic scanning options include four tools avset sails mrle mpda up to 3 extra cells aloft <20 nm from rda could cause problems avset button opens gui 18 dbz < 80 sq. km 30 dbz < 30 sq. km 18 dbz increase by < 12 sq. km since last volume scan avest in a nutshell what is it? what is it? what is it? what is it? how does it work? how does it work? how does it work? how does it work? when can i use it? when can i use it? when can i use it? when can i use it? where do i apply it? where do i apply it? where do i apply it? where do i apply it? pros & cons pros & cons pros & cons pros & cons last tilt regardless of 18 & 30 dbz coverage avset continues: conditions met avset continues: conditions not met avset starts to check area of 18 & 30 dbz: conditions not met example: avset in action 0.5° 0.9° 1.3° 1.8° 2.4° 3.1° 4.0° 5.1° 6.4° 8.0° 10.0° more frequent sampling here less frequent sampling everywhere else sails button opens gui sailsx1: extra 0.5° after these tilts sailsx2,x3: extra 0.5° scans evenly spaced sails scan placement varies volume to volume up to 3 extra tilts sails in a nutshell what is it? what is it? what is it? what is it? how does it work? how does it work? how does it work? how does it work? when can i use it? when can i use it? when can i use it? when can i use it? where do i apply it? where do i apply it? where do i apply it? where do i apply it? pros & cons pros & cons pros & cons pros & cons sails tilt #2 sails tilt #1 example: sails in action 0.5° 0.9° 0.5°* 1.3° 1.8° 2.4° 0.5°** 3.1° 4.0° 5.1° 6.4° more frequent sampling here less frequent sampling everywhere else mrle button opens gui an extra scan of up to the 2-4 lowest tilts mrle: tilts inserted mid-scan up to 4 extra tilts mrle in a nutshell what is it? what is it? what is it? what is it? how does it work? how does it work? how does it work? how does it work? when can i use it? when can i use it? when can i use it? when can i use it? where do i apply it? where do i apply it? where do i apply it? where do i apply it? pros & cons pros & cons pros & cons pros & cons radar back to collecting standard vcp 212 data collection of mrle extra tilts begins last tilt prior to collecting supplemental scans example: mrle in action 0.5° 0.9° 0.5°* 1.3° 1.8° 2.4° 0.9°* 3.1° 4.0° 5.1° 6.4° 1.3°* 1.8°* 8.0° allows for more complete v & sw data on lowest two tilts comes at cost of longer scan times (especially w/sails enabled) add mpda button opens gui mpda available for sails (but nor mrle) tilts in vcps 212 & 215 mpda can be enabled for 212 & 215, but is always enabled for vcp 112 extra cd rotation collected on mpda tilts (1 cs, 2 cd) to recover nearly all v & sw data extra rotations lengthen volume scan times minimize range folding on lowest 1 or 2 tilts mpda in a nutshell what is it? what is it? what is it? what is it? how does it work? how does it work? how does it work? how does it work? when can i use it? when can i use it? when can i use it? when can i use it? where do i apply it? where do i apply it? where do i apply it? where do i apply it? pros & cons pros & cons pros & cons pros & cons toggle to mpda off toggle to mpda off toggle to mpda off toggle to mpda off toggle to mpda on toggle to mpda on toggle to mpda on toggle to mpda on example: mpda in action toggle to mpda on toggle to mpda on toggle to mpda on toggle to mpda on how/when should i use these features? levels of guidance varies based on the feature: avset: straight forward sails/mrle/mpda: more complicated roc has new tool to aid offices with these settings called preset configurations! the presets offer a starting point, but your office’s radar needs on a given day may be different we will provide some additional guidance for customizing those settings further guidance on avset usage easy decision: just use it elevated convection & avset cells aloft <20 nm from rda could cause problems other dynamic scanning guidance preset configurations provide standard setups first 5: defaults from the roc & not editable second 5: available for local customization key point: 5 defaults serve as a good starting point for sails/mrle/mpda use unfortunately, this is the real world tornado? hail? multiple threats? when there are multiple threats, focus on the big toe sails/mrle/mpda selection should be focused on primary threat hedge settings for secondary & tertiary threats closer to the radar, adding sails or mrle: increases low-level tilts some decreases upper-level tilts more primary threat secondary threat tertiary threat(s) when adapting presets, each threat has different focus tornado hail wind 40 kft 20 kft 10 kft 5 kft each threat has different focus areas in the storm example: sails vs. mrle use for tornadic events 40 kft 20 kft 10 kft 5 kft preferred layer for tornadogenesis observation preferred layer for tornadogenesis observation closer to the radar: mrlex4 samples a little better than sailsx3 farther away from radar: sailsx3 better than mrlex4 key point: outside of ~15 nm, either option is better than no extra scans for tornadoes sails/mrle/mpda use: “food for thought” most important point: don’t “set it and forget it”! enable supplemental scans for precip accumulation! adding extra tilts make volume scan longer longer volume scan times can lead to artifacts in qpe data update the adaptable parameter to fix sails/mrle & warning performance kingfield and french (2022) proper use of sails/mrle during expected severe weather should improve performance in summary discussed the main dynamic scanning options available at the wsr-88d: avset sails mrle mpda introduced preset configurations to help forecasters with dynamic scanning decision-making discussed how sails/mrle setting adjustments impact sampling & how you might adjust from the defaults correct correct! avset shortens volume scans by eliminating unnecessary tilts aloft. continue continue continue continue continue continue incorrect incorrect. shortening a vcp will not make it slower. continue continue continue continue continue continue incorrect incorrect. lengthening a vcp will not make it faster. continue continue continue continue continue continue incorrect incorrect. avset’s goal is the opposite of this option. continue continue continue continue continue continue lengthen, faster lengthen, faster lengthen, faster lengthen, faster lengthen, faster lengthen, faster lengthen, slower lengthen, slower lengthen, slower lengthen, slower lengthen, slower lengthen, slower shorten, slower shorten, slower shorten, slower shorten, slower shorten, slower shorten, slower shorten, faster shorten, faster shorten, faster shorten, faster shorten, faster shorten, faster the purpose of avset is to _____ a vcp in order to make the update time for products _____. incorrect incorrect. none of the dynamic scanning sessions address this issue. continue continue continue continue continue continue incorrect incorrect. this statement describes sails, not mrle. continue continue continue continue continue continue incorrect incorrect. avset’s goal is to increase the frequency of volume scans, not mrle’s goal. continue continue continue continue continue continue correct correct! mrle increases sampling of the lower levels of the atmosphere by adding up to four additional low level tilts per volume scan. continue continue continue continue continue continue increase the sampling of the lower levels of the atmosphere increase the sampling of the lower levels of the atmosphere increase the sampling of the lower levels of the atmosphere increase the sampling of the lower levels of the atmosphere increase the sampling of the lower levels of the atmosphere increase the sampling of the lower levels of the atmosphere increase the frequency of volume scans increase the frequency of volume scans increase the frequency of volume scans increase the frequency of volume scans increase the frequency of volume scans increase the frequency of volume scans increase the frequency of 0.5 scans available to forecasters increase the frequency of 0.5 scans available to forecasters increase the frequency of 0.5 scans available to forecasters increase the frequency of 0.5 scans available to forecasters increase the frequency of 0.5 scans available to forecasters increase the frequency of 0.5 scans available to forecasters increase data quality for elevated convection near the rda increase data quality for elevated convection near the rda increase data quality for elevated convection near the rda increase data quality for elevated convection near the rda increase data quality for elevated convection near the rda increase data quality for elevated convection near the rda the purpose of mrle is to _____. incorrect you did not select the correct response. continue continue continue continue continue continue correct that's right! you selected the correct response. continue continue continue continue continue continue 12, 212, 215 12, 212, 215 12, 212, 215 12, 212, 215 12, 212, 215 12, 212, 215 12, 34, 212 12, 34, 212 12, 34, 212 12, 34, 212 12, 34, 212 12, 34, 212 35, 112, 215 35, 112, 215 35, 112, 215 35, 112, 215 35, 112, 215 35, 112, 215 34, 35, 12 34, 35, 12 34, 35, 12 34, 35, 12 34, 35, 12 34, 35, 12 which one of the following groups only includes vcps for which avset can be active? incorrect you did not select the correct response. continue continue continue continue continue continue correct that's right! you selected the correct response. continue continue continue continue continue continue true true true true true true false false false false false false avset is designed to be very sensitive to potentially developing convection aloft. incorrect you did not select the correct response. continue continue continue continue continue continue correct that's right! you selected the correct response. continue continue continue continue continue continue avset avset avset avset avset avset sails sails sails sails sails sails mrle mrle mrle mrle mrle mrle mpda mpda mpda mpda mpda mpda preset configurations available at the rpg hci allow forecasters to assign which of the following dynamic scanning options based on saved settings in one action: incorrect incorrect. sailsx3 cannot be invoked by both of these vcps. continue continue continue continue continue continue correct correct! continue continue continue continue continue continue true true true true true true false false false false false false sailsx3 can be invoked for vcps 112 and 215. incorrect incorrect. data from sails tilts can help eliminate this issue (at least in the dual-pol qpe products). continue continue continue continue continue continue incorrect incorrect. sailsx3 is only available on vcps 12 & 212. continue continue continue continue continue continue incorrect incorrect. radar operators shouldn’t have a “set it and forget about it” mindset towards sails. continue continue continue continue continue continue correct correct! continue continue continue continue continue continue radar operators should set the number of sails tilts at the rpg or awips and not think about it for the rest of the event. radar operators should set the number of sails tilts at the rpg or awips and not think about it for the rest of the event. radar operators should set the number of sails tilts at the rpg or awips and not think about it for the rest of the event. radar operators should set the number of sails tilts at the rpg or awips and not think about it for the rest of the event. radar operators should set the number of sails tilts at the rpg or awips and not think about it for the rest of the event. radar operators should set the number of sails tilts at the rpg or awips and not think about it for the rest of the event. multiple sails tilts are available for use on vcps 12, 35, 212, and 215. multiple sails tilts are available for use on vcps 12, 35, 212, and 215. multiple sails tilts are available for use on vcps 12, 35, 212, and 215. multiple sails tilts are available for use on vcps 12, 35, 212, and 215. multiple sails tilts are available for use on vcps 12, 35, 212, and 215. multiple sails tilts are available for use on vcps 12, 35, 212, and 215. sails tilts are distributed in time to ensure they are collected at evenly spaced intervals. sails tilts are distributed in time to ensure they are collected at evenly spaced intervals. sails tilts are distributed in time to ensure they are collected at evenly spaced intervals. sails tilts are distributed in time to ensure they are collected at evenly spaced intervals. sails tilts are distributed in time to ensure they are collected at evenly spaced intervals. sails tilts are distributed in time to ensure they are collected at evenly spaced intervals. enabling sails has no impact on data artifacts on precipitation products due to fast moving storms. enabling sails has no impact on data artifacts on precipitation products due to fast moving storms. enabling sails has no impact on data artifacts on precipitation products due to fast moving storms. enabling sails has no impact on data artifacts on precipitation products due to fast moving storms. enabling sails has no impact on data artifacts on precipitation products due to fast moving storms. enabling sails has no impact on data artifacts on precipitation products due to fast moving storms. which of the following statements about sails use is true. andrew.c.wood@noaa.gov <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Welcome to the lesson on Dynamic Scanning. This lesson is part of the Principles of Meteorological Doppler Radar topic in the Radar & Applications Course. Let’s get started!"> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Most NWS employees taking this lesson have just started their career, so it’s possible you have not had the life experience of purchasing a new vehicle. I’ve been through this process several times now, and it amazes me the number of ways you can customize vehicles. Even if you just narrow it down to one category, like safety features, you might have several options at your disposal. You can toggle on and off features like anti-lock brakes, proximity alerts, or whether you are changing lanes. Other features, like adaptive cruise control, allows you to choose how close you can get to the car in front of you before it slows you down. When you are first introduced to these options on the lot, they are cool. Once you own the car and start driving it around, you have to figure out how this cornucopia of features work best for you. Are the default setting ok. If I configure something wrong, will it lead to an accident. For some, this learning process is fun. For others, it can be very annoying, frustrating, or even terrifying. Well, this situation is analogous to understanding and applying dynamic scanning strategies on the WSR-88D. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Let me start by explaining what is dynamic scanning. Dynamic scanning features allow your office to adjust the WSR-88D volume scan to better meet your needs. You can customize (to some degree) how the radar collects data. These adjustments are powerful, but can be confusing to implement. Forecasters want to know the best choice to make with these various scanning strategies, but there is often not one obvious right answer. So, thinking that way can be an issue. Additionally, the amount of research done on the topic of which scanning strategies are best has been limited. While we will touch on this work in this lesson, our primary focus will be on a two step approach. First, we will explain the various dynamic scanning options. Then, we will explain some basic principles on how to apply them in an operational setting. My goal is change your mindset from picking the right choice every time to thinking of the tradeoffs involved with using these tools in your current situation."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Dynamic scanning at the WSR-88D involves four tools that can adjust your volume coverage pattern (or VCP) on a scan by scan basis, as neeed. These applications may be available in some VCPS, but not others. They may be available in different degrees, too. These four tools are: the Automated Volume Scan Evaluation and Termination (or AVSET), the Supplemental Adaptive Intra-Volume Low-Level Scan (or SAILS), the Mid-Volume Rescan of Low-Level Elevations (or MRLE), and the multiple PRF Dealiasing Algorithm (or MPDA). We will explain the details of each feature in the next several slides."> <Style FontSize="14" /> </Span> <Span Text="
" /> </Block> <Block> <Style /> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text="Base Layer: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="Let’s start our dynamic scanning strategy discussion with AVSET. Use the buttons on the left to learn more about this application.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="What Is It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="AVSET analyzes data collected at higher elevation angles and determines if further scanning aloft is necessary. Using AVSET prevents the collection of radar data at elevations where it isn’t meteorologically necessary.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="How Does It Work?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="When enabled, AVSET analyzes the first scan collected above 5 degrees. If the Reflectivity data do not meet certain power and areal coverage thresholds, then it targets the following elevation angle as the final one in the volume scan. Those thresholds are:
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="16" FirstLineMargin="0"> <ListStyle ListType="Bullet" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="18 dBZ echoes cover less than 80 km2
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="16" FirstLineMargin="0"> <ListStyle ListType="Bullet" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="30 dBZ echoes cover less than 30 km2 and
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="16" FirstLineMargin="0"> <ListStyle ListType="Bullet" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="18 dBZ echo coverage increases by less than 12 km2 since the last volume scan.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="When Can I Use It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="AVSET is available for use on all precipitation mode VCPs, so it can be used on VCPs 12, 112, 212, and 215.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Where Do I Apply It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="AVSET can be toggled on an off in two ways. You can do it at the RPG HCI by choosing the AVSET button on the interface. That will display a GUI making you verify your choice. You can also change the setting on your AWIPS workstations using the VCP/VMI Change Request GUI.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Pros and Cons: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="The primary benefit of AVSET is the potential for faster volume scans which can lead to more volume scans over time (up to 1 scan per hour more with each tilt removed). The primary downside of using AVSET is the potential for missing elevated convection that develops near the RDA. Those situations are uncommon and usually short-lived.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0"> <ListStyle ListType="None" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text=""> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" This interaction shows an actual volume scan where AVSET is enabled and criteria for termination are ultimately met. Use the slider bar on the left-hand side of the slide to look at each elevation angle of data. Once you get to 5.1 degrees, you will see notes detailing whether the AVSET criteria or met on that tilt. Once you are done viewing the interaction, use the next button to advance to the next slide."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text="Base Layer: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="Use the buttons on the left to learn more about SAILS.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="What Is IT?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="SAILS (or you might have even heard it referred to as MESO-SAILS) allows you to add additional scans of the lowest elevation angle tilt in each volume scan. Depending your VCP, you can add up to 3 SAILS tilts per volume scan.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="How Does it Work?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="When you add SAILS tilts to your volume scan, the RPG attempts to place all of the lowest level tilts (which is usually 0.5 degrees) evenly throughout the volume scan. Since each tilt takes different lengths of time to complete based on the scanning strategy used, the number of tilts between each lowest-level tilt will not be the same. If, for example, you use VCP 212 with SAILSx1 and a full volume scan is collected, than the extra 0.5 degree tilt will be collected after the 2.4 or 3.1 degree tilts. Those placements will change quite a bit when you use SAILSx2 or x3, if AVSET terminates the volume scan early, or if you enable MPDA. The important thing to remember is the RPG tries to place the scans evenly in time based on what happened in the previous volume scan.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="When Can I Use It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="SAILS is available in some form in every VCP except 31, but your options vary. VCPs 12 and 212 allow for up to 3 SAILS tilts per volume scan. VCPs 34, 35, 112, and 215 allow for one SAILS tilt per volume scan.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="Where Do I Apply It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="SAILS"> <Style FontSize="14" FontIsBold="False" /> </Span> <Span Text=" can be toggled on an off in two ways. You can do it at the RPG HCI by choosing the SAILS button on the interface. That will display a GUI where you can choose the number of SAILS tilts to enable. You can also change the setting on your AWIPS workstations using the VCP/VMI Change Request GUI. SAILS may also be disabled at the RPG or AWIPS if you choose to enable MRLE because SAILS and MRLE cannot be used concurrently.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="Pros & Cons: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="The benefit of enabling SAILS is you get more frequent sampling of the atmosphere on the tilt closest to the ground. The downside to collecting data more frequently in that part of the atmosphere is that your volume scans take longer to complete, resulting in less frequent scanning of the rest of the atmosphere. So, there’s a clear tradeoff."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" This interaction shows an actual volume scan where SAILS was enabled. Use the slider bar on the left-hand side of the slide to look at each elevation angle of data. The SAILS tilts will be annotated with an asterisk in the slider labels and annotated on the upper left-hand-side of the graphic. Once you are done viewing the interaction, use the next button to advance to the next slide."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text="Base Layer: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="Use the buttons on the left to learn more about MRLE.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="What Is It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="MRLE allows you to add additional scans to get a second sampling of a low-level layer of the atmosphere. When MRLE is enabled, you can have an additional tilt of the 2-4 lowest elevation angles per volume scan.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="How Does It Work?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="When MRLE is enabled, it will identify the midway point of the volume scan based on the previous tilt. Once it completes an elevation tilt at that mid-point, the radar will drop back down to the lowest elevation angle. If we use a full VCP 212 volume scan and enable MRLEx4, the radar would stop between the 5.1 and 6.4 tilts. It will then proceed to collect the lowest few tilts again (depending on your choice). Once it has completed those additional scans, it will return to collect the 6.4 degree and higher data to complete the volume scan.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="When Can I Use It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="MRLE is available on three VCPs: 12, 212, and 215.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="Where Do I Apply It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="MRLE"> <Style FontSize="14" FontIsBold="False" /> </Span> <Span Text=" can be toggled on an off in two ways. You can do it at the RPG HCI by choosing the MRLE button on the interface. That will display a GUI where you can choose the number of MRLE tilts to enable. You can also change the setting on your AWIPS workstations using the VCP/VMI Change Request GUI. MRLE may also be disabled at the RPG or AWIPS if you choose to enable SAILS because SAILS and MRLE cannot be used concurrently.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="Pros & Cons: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="The advantage of using MRLE is you can more frequently sample a low-level layer of the atmosphere. What that layer includes will depend on how far away from the radar your target is located. The disadvantages of MRLE include longer volume scan times and less frequent sampling of the atmosphere outside of that layer. So, once again, you have a clear tradeoff between using and not-using MRLE."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" This interaction shows an actual volume scan where MRLE was enabled. Use the slider bar on the left-hand side of the slide to look at each elevation angle of data. The supplemental MRLE tilts will be annotated with an asterisk in the slider labels. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text="Base Layer: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="Use the buttons on the left to learn more about MPDA.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="What Is It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="MPDA is a velocity dealiasing algorithm that will be explained in greater detail in the lesson that covers that topic. Implementing this algorithm helps to minimize the area of range folded velocity data. Starting with RDA/RPG Build 23, this algorithm can be implemented in VCPs 212 and 215 for the lowest one or two tilts.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="How Does It Work?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="MPDA works by having the WSR-88D collect three full cuts (one CS waveform and two CD waveform) on an elevation angle in order to minimize areas of range folding. A more detailed description will be given in the Velocity Deailiasing lesson. Each tilt where that extra cut is collected takes about 20 seconds longer to complete than volume scans when MPDA isn’t used. That longer data collection time for these tilts (especially when MPDA is used in conjunction with SAILS) can have a significant impact on volume scan timing. The ability to enable or disable the algorithm along with the time difference when implemented is why we include it in the discussion with this lesson.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="When Can I Use It?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="MPDA can be toggled on and off on VCPs 212 and 215. MPDA can be added when SAILS tilts are enabled (regardless of number), but cannot be implemented when MRLE is used. NOTE: MPDA is always enabled for the lowest three elevation angles on VCP 112.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="Where Do I Apply it?: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="Currently, you can only enable this feature by choosing the “Add MPDA” button on the interface at the RPG HCI. That will display a GUI where you can choose the number of MPDA tilts to enable. MPDA may also be disabled at the RPG or AWIPS if you choose to enable MRLE since MPDA and MRLE cannot be used concurrently.
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="
"> <Style FontSize="14" /> </Span> </Block> <Block> <Style /> <Span Text="Pros and Cons: "> <Style FontSize="14" FontIsBold="True" /> </Span> <Span Text="The upside of the MPDA algorithm is that it allows forecasters to significantly reduce the areas of range folding in velocity products. The downside is using this technique adds approximately 20 seconds for each tilt that implements it. Enabling SAILSx3 and MPDA will add over 1 minute per volume scan. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" This interaction shows actual data comparing MPDA’s impact on radial velocity data. Use the button on the slide to toggle back and forth between the two radars. One will show VCP 212 data with MPDA enabled (KCRI) and the other shows VCP 212 data without MPDA enabled (KTLX). "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Now that I’ve described what these dynamic scanning strategies are, how should use them operationally? That depends on the tool. AVSET is straight forward but the others are more complicated. Fortunately, the ROC has developed a new tool in RPG Build 24 that will aid offices called Preset Configurations. The presets offer offices a starting point VCP and dynamic scanning settings for several scenarios and allow local offices to add additional options. Your local needs may vary significantly from the default or custom presets you build in any given situation. We will offer some suggestions on how to adjust your dynamic scanning strategies from the presets you office has available on a later slide."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" The guidance on using AVSET is fairly straight-forward: Just use it. As you can see from this VCP status monitor table, most offices do just that because there’s almost no practical downside to it. It’s important that we tell you that explicitly just in case you find yourself in a situation where it has been turned off and wonder if you should enable it. The answer to that question is generally yes you should!"> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" If you find yourself in a situation where you have AVSET enabled and elevated convection occurs near the RDA, you could potentially miss cells within the nearest 20 nm of the RDA…at least a volume scan or two. If you suspect that your radar is not detecting elevated cells in your primary radar’s cone of silence, switch to another nearby radar to monitor the storms. It doesn’t have to be a WSR-88D, either. Consider using a nearby TDWR if you have one. If the convection becomes significant, it should prevent AVSET from truncating the volume scan until the precipitation starts to reach closer to the surface."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" As mentioned previously, the Preset Configuration window contains several standard configurations for specific meteorological situations. These five default configurations are provided by the Radar Operations Center these general weather scenarios. The Preset Configuration Management window also has room for five custom configurations for local offices to configure for their various needs. It’s important to remember that not all of these situations are alike. So, consider these settings as good starting points. The weather on any given day (or at any particular moment in that day) may lead you to further adjust what you have in these settings. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" For example, you could have situation like this going on in your area. Southeast of the radar, you have a potentially tornadic supercell. West-southwest of the radar, there’s another supercell that could be producing large hail. North and east of the radar, multiple threats from flash flooding to a developing QLCS with significant winds and hail are possible. How are you to choose a preset configuration (and then possibly adjust it) to meet your needs in such a situation?"> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" When you are facing multiple, varying threats, you should focus on the “big toe”. In other words, which phenomenon is the primary threat? In the previous example, it would likely be the potentially tornadic supercell. So, the Supercell preset is a valid starting point. From there, you can hedge the settings to accommodate the secondary and tertiary threats, if warranted. In this case, that could be reducing your SAILS tilt to 1 or maybe even going with 2 MRLE tilts depending on what you were most concerned with in this scenario. The important thing to remember, increasing your SAILS/MRLE tilts will increase the number of low-levels tilts available a litlte bit, but it will have a larger decrease on the number of upper-level tilts more. So, you need to be aware of the tradeoff involved."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" When adapting your preset configuration, it’s important to remember that each threat has a different area of focus. I use this WAY too simplistic graphic to highlight. Adding SAILS and MRLE tilts increases the sampling focus near the surface at the cost of sampling aloft. The range of the threats plays an important part in this calculus, too. Threats located far from the radar may not be sampled well near the surface where as these same storms located next to the radar may be undercut if you only focus on the lowest tilt. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Let’s use tornadic events as a specific example. Remember that the preset configuration recommends SAILSx2 for supercells to increase low-level scans near the surface which would better sample the preferred layer for tornadogenesis compared to a standard VCP 212 volume scan. If a potentially tornadic storm was located fairly close to the radar, using MRLE might be a better option than SAILS because it would allow you to more completely sample the layer of interest with potentially more scans (say, if you compare MRLEx4 to SAILSx3). However, if that same storm is located relatively far from the radar, than SAILSx3 would be a significantly better option that MRLE. The Preset Configuration tries to cover the most possible situations, hence the reason SAILSx2 is the default for supercells. An important point I want to make is that regardless if you use SAILS or MRLE in this situation, either will provide better coverage of this lower layer of the atmosphere than having neither enabled unless the storm is significantly in the cone of silence (within 15 nm of the radar) where even those higher tilts will still be scanning below 10,000 ft. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Radar operators have multiple SAILS, MRLE, and MPDA options at their disposal. If you only remember one thing from this dynamic scanning conversation, it should be this: Don’t simply “set and forget” these features. You should routinely review the needs of the current event and adjust your SAILS, MRLE, and MPDA settings accordingly. Even when using the standard Preset Configurations, you want to make sure they still address your primary concern for the event."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Rapidly moving, discrete cells can lead to artifacts in both the QPE and PPS products. An example of one of these artifacts is shown on the slide. Fortunately, the QPE products can address this issue by incorporating data from the supplemental tilts in the estimates. The RPG HCI has an adaptable parameter for the dual-pol algorithms called “Enable use of supplemental scans”. Here’s how the same data might look when this feature is enabled. This change doesn’t impact the legacy PPS products at all. Also, the SAILS data will not help where beam blockage causes the Hybrid Hydrometeor Classification algorithm to use data from a higher elevation angle. So, you will need to balance these two caveats with the desire for smoother dual-pol QPE products. "> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Before wrapping up this lesson, I want to leave you with one more nugget of information. Some recent studies have looked at NWS warning performance in the context of SAILS/MRLE use. While those studies show that offices that used SAILS/MRLE during severe weather operations had improved warning statistics compared to events where dynamic scanning was not enabled, these studies don’t show a conclusive cause and effect relationship…at least not yet. Having said that, the vast number of cases in these studies does suggest that proper SAILS and MRLE usage during severe weather operations could benefit forecasters’ warning performance. As more work is done in this area, we will update our guidance regarding SAILS and MRLE usage for forecasters."> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" In summary, the lesson discussed the main dynamic scanning strategies available at WSR-88D sites. These are AVSET, SAILS, MRLE, and MPDA. AVSET’s guidance is straight-forward…just use it. The others are more complicated. Fortunately, the ROC recently provided Preset Configurations to help forecasters make these choices. This tool provides default settings for common situations and empty slots for offices to create their own. Even with this tool, you may need to deviate from these settings based on the current weather, especially if you have multiple threats in your area. We ended our conversation by discussing how SAILS/MRLE changes impact the number of tilts you collect at different layers of the atmosphere. In turn, those changes can be used to adjust your dynamic scanning settings away from the presets. Regardless of whether you use a default setting for a common situation or have configured the radar to meet the specific needs of the day, don’t just set it and forget it!"> <Style FontSize="14" /> </Span> </Block> </Content> </Document> <Document xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Content> <Block> <Style /> <Span Text=" Congratulations on completing this lesson. Please feel free to use the email addresses on this slide to contact us with any questions you have about this lesson."> <Style FontSize="14" /> </Span> </Block> </Content> </Document>