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Slide Text Space SUBMIT ALL submit all SUBMIT submit Submit Unmute volume principles of doppler meteorological radar recombination at the rpg instructor: andy wood review lesson take your time and review the lesson content provided in this presentation. review lesson technical problems? if you encounter any technical problems with this lesson, please contact the rac team directly by e-mail at: nws.wdtd.rachelp@noaa.gov technical problems? complete the quiz at the end of this lesson, there is an embedded quiz. complete this quiz by selecting the best answer for each question. you need to correctly answer 70% of the quiz questions to receive completion credit in the lms. complete the quiz course completion review lesson review lesson complete the quiz technical problems? technical problems? introduction in order for nws forecasters to receive credit for this course in the nws learning center, you will need to take the following steps roadmap learning objectives identify the purposes of the different recombination tasks at the rpg recombination at the rpg two reasons for recombination: split cut dual-pol base data too noisy * exception: two “raw” products discussed later super-res base data recombined from 0.5° to 1.0° azimuth for rpg algorithms dual-pol recombination at rpg split cut dual-pol data recombined from 0.5° to 1.0° azimuth zdr pre-processed too noisy zdr post-processed smoothed & recombined dual-pol azimuthal recombination combines two 0.5° bins into one 1.0° bin no range recombination, but smoothed later example of dual-pol recombination hail core zdr arc? example of dual-pol recombination hail core zdr arc? same example, but numeric data 0.63 -0.81 -0.19 -0.58 0.44 1.31 2.38 0.06 0.38 0.31 0.31 -0.19 0.56 1.00 0.75 1.69 -1.31 1.13 original level ii zdr values: 0.47 -0.25 -0.19 0.00 0.72 1.03 2.04 -0.63 0.76 recombined level ii zdr values: 0.44 0.06 0.13 0.19 0.69 0.56 0.75 0.94 0.69 level iii zdr (pre-processed) values: legacy data recombination at rpg original\early rpg algorithms cannot ingest sr base data tda pps vil reflectivity recombination linear average of 8 bins no data bins: power estimated & z used in average velocity & spectrum width recombination recombination for velocity & spectrum width power weighted averages sw: also accounts for velocity estimate variance summary recombination at the rpg has two goals: combine dual-pol base data to provide better inputs to forecasters and algorithms azimuthal recombination only further noise reduction occurs at dual-pol pre-processor combine legacy doppler data for algorithms created prior to super-res implementation z: azimuthal and range recombination v & srm: azimuthal recombination only incorrect incorrect: for the batch and higher elevations, range recombination is performed on the reflectivity base data. continue continue continue continue continue continue incorrect incorrect: there is no need for merging these two data resolutions. continue continue continue continue continue continue correct correct. continue continue continue continue continue continue incorrect incorrect: legacy recombination does not generate any products. continue continue continue continue continue continue question #1 of 2 which one of the following statements concerning recombination of legacy base data is true? legacy recombination generates super resolution base products. legacy recombination generates super resolution base products. legacy recombination generates super resolution base products. legacy recombination generates super resolution base products. legacy recombination generates super resolution base products. legacy recombination generates super resolution base products. legacy recombination is required because most of the legacy radar product generator (rpg) algorithms cannot process super resolution base data. legacy recombination is required because most of the legacy radar product generator (rpg) algorithms cannot process super resolution base data. legacy recombination is required because most of the legacy radar product generator (rpg) algorithms cannot process super resolution base data. legacy recombination is required because most of the legacy radar product generator (rpg) algorithms cannot process super resolution base data. legacy recombination is required because most of the legacy radar product generator (rpg) algorithms cannot process super resolution base data. legacy recombination is required because most of the legacy radar product generator (rpg) algorithms cannot process super resolution base data. legacy recombination merges super and legacy resolution data into one product. legacy recombination merges super and legacy resolution data into one product. legacy recombination merges super and legacy resolution data into one product. legacy recombination merges super and legacy resolution data into one product. legacy recombination merges super and legacy resolution data into one product. legacy recombination merges super and legacy resolution data into one product. there is no recombination of base data performed above the split cuts. there is no recombination of base data performed above the split cuts. there is no recombination of base data performed above the split cuts. there is no recombination of base data performed above the split cuts. there is no recombination of base data performed above the split cuts. there is no recombination of base data performed above the split cuts. incorrect incorrect: the rda does not produce .25 degree azimuth base data continue continue continue continue continue continue incorrect incorrect: the recombination is intended to lower the resolution continue continue continue continue continue continue incorrect incorrect: these data are not ready, since they first require recombination continue continue continue continue continue continue correct correct. continue continue continue continue continue continue question #2 of 2 the dual-pol base data are recombined at the rpg from ____ of azimuth to ____ because these data are ____ for direct product generation. 0.5 degree; 1.0 degree; too noisy 0.5 degree; 1.0 degree; too noisy 0.5 degree; 1.0 degree; too noisy 0.5 degree; 1.0 degree; too noisy 0.5 degree; 1.0 degree; too noisy 0.5 degree; 1.0 degree; too noisy 0.5 degree; 1.0 degree; ready 0.5 degree; 1.0 degree; ready 0.5 degree; 1.0 degree; ready 0.5 degree; 1.0 degree; ready 0.5 degree; 1.0 degree; ready 0.5 degree; 1.0 degree; ready 1.0 degree; 0.5 degree; too noisy 1.0 degree; 0.5 degree; too noisy 1.0 degree; 0.5 degree; too noisy 1.0 degree; 0.5 degree; too noisy 1.0 degree; 0.5 degree; too noisy 1.0 degree; 0.5 degree; too noisy 0.25 degree; 0.5 degrees; ready 0.25 degree; 0.5 degrees; ready 0.25 degree; 0.5 degrees; ready 0.25 degree; 0.5 degrees; ready 0.25 degree; 0.5 degrees; ready 0.25 degree; 0.5 degrees; ready roadmap <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Welcome to the Radar & Applications Course Principles of Doppler Weather Radar. This lesson discusses base data recombination at the Radar Product Generator or RPG. Let’s get started."> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.31999969" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Here is the complete roadmap for the entire “Principles of Doppler Weather Radar” topic of RAC. You are currently in the Base Data Quality Management section of that topic."> <Style FontFamily="Open Sans" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" ForegroundColor="#444444" Elevation="Normal" DisplayCase="AsIs" LinkColor="#444444" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Span Text="There’s one learning objective for this lesson. Please take a moment to review the objective, as the quiz at the end of this lesson is based on it."> <Style FontSize="11" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Recombination at the RPG is the process of combining range bins of Level II base data azimuthally, radially, or both. Why might we want to recombine radar data to give ourselves coarser data resolution? There are two reasons for this process at the RPG:
"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="
"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="1. The super-res, Level II dual-pol data are very noisy. Too noisy for routine human or algorithm analysis. Recombining the data on the Split cut elevations helps eliminate some of that noise.
"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="
"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="2. Likewise, some of the original RPG algorithms were developed using standard resolution radar data as input. Those algorithms have not been updated to input super-resolution data for legacy Doppler products (such as base reflectivity, base velocity, and spectrum width)."> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="The RDA sends dual-pol base data to the RPG. Those data include Differential Reflectivity, Correlation Coefficient, and Differential Phase. On the Split Cut elevations, these data streams have 0.5° azimuthal resolution. You can see an example of such data on the left. While signals can be seen in this data, the noise present makes it difficult to sample a single range bin and feel that it is representative of the meteorological signal in the data. Recombination (along with radial smoothing at the dual-pol pre-processor which will be discussed in the next lesson) produce the product on the right. These data now have a 1.0° azimuthal resolution and provide a much easier product for meteorological analysis."> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Dual-pol base data recombination averages the power-weighted values of two adjacent 0.5° range bins into one 1.0° range bin. Since the range resolution stays the same, no range recombination is required. However, more filtering of these data will occur at the dual-pol preprocessor. If both bins are assigned No Data or range-folded, then the legacy bin is also assigned No Data or range-folded (RF). If one of the two super resolution bins is assigned No Data or RF, then the remaining valid bin is assigned as the legacy resolution value. "> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Span Text="Let’s look at an example to see why dual-pol recombination and smoothing (which will be discussed in the next lesson) matters. Here’s Differential Reflectivity Level II data. We will focus our attention on this range bin here since it’s at the center of the action. To interpret these data properly, you need to look at this image in context to other data. For the sake of time, let me point out some key features present. To the west and northwest of our range bin, there’s a hail core. See the generally lower Zdr values there. A few kilometers to the east, we have an area of larger rain drops that might be a developing Zdr arc. Let’s see what this same image looks like after recombination and dual-pol preprocessing has occurred."> <Style FontSize="11" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Span Text="Here’s the Level III data for the same place and time. We have highlighted the same range bin at the center of it all right here. The Zdr values in the hail core are a little higher than in the raw data. The high values in the potential Zdr arc have been smoothed out as well. While these two features would likely be detectable in the raw Level II data, you see the overall patterns in the data much easier in the recombined and smoothed data. Let’s look at the numbers in a little more detail to see why that is."> <Style FontSize="11" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Span Text="Here are the actual Zdr values from the Level II data. The range bin I pointed out previously is highlighted in orange. I have included several range bins around this one for context as we talk about smoothing the data. So, why not just recombine the data and call it good. Well, here’s what you get when you just recombined the super-res data into standard resolution. These data remain very noisy at this point. Now let’s look at the recombined AND smoothed data. Even though the value in our range bin barely changed, you can see some major changes in the bins that surround it. Some of these data are 1 dB or more different than the original data for that location. That high amplitude noise for Zdr! We will revisit the significance of this some more in the next lesson."> <Style FontSize="11" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="Now let’s move on to the second goal of recombination. The original RPG algorithms rely on standard resolution or coarser base data to function. In fact, most algorithms developed prior to super-resolution base data being available fall into that category. In fact, these algorithms were designed for reflectivity input with 1° azimuthal resolution and 1 km range resolution. For Velocity and Spectrum Width, the algorithms require 1° azimuthal resolution and 250 m range resolution. Examples of such algorithms include the Tornado Detection Algorithm, the Legacy Precipitation Processing System algorithm, and Vertically Integrated Liquid (which is shown here on the slide). "> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="So, how does Reflectivity recombination work? This image should help. You can see eight super resolution range bins are averaged linearly into one range bin of 1.0° azimuth by 1 km range resolution. For bins assigned No Data, the RPG estimates the associated power, converts that value to Z and included in the average. The RPG does not produce a product that displays Reflectivity at this resolution any more, so the recombined data are only internal to the RPG algorithms."> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.32" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="A similar process occurs for the Velocity and Spectrum Width products. For these products, the RPG algorithms require 1.0° azimuth by .25 km range resolution for input. So, the RPG recombines these data azimuthally, only. Recombination performs a power weighted average of the two super resolution bins into the one corresponding standard resolution bin. For Spectrum Width, an additional step accounts for the variance of the two corresponding velocity values in the final spectrum width value. If both bins are assigned No Data or range-folded, then the legacy bin is also assigned No Data or range-folded (RF). If one of the two super resolution bins contains data and the other is assigned No Data or RF, then the remaining valid bin is assigned as the legacy resolution value."> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Normal" DisplayCase="AsIs" LinkColor="dk1,00" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Span Text="In summary, recombination at the RPG has two goals. The first goal of recombination is to combine the dual-pol base data to eliminate noise and make the data more usable for forecasters and algorithms alike. The RPG combines the products azimuthally, but further smoothing to reduce noise occurs at the dual-pol pre-processor. The second goal of recombination involves supporting older RPG algorithms developed prior to super-res data being available. These products require that standard resolution data (or coarser in the case of Reflectivity) be used as input. Reflectivity data are combined azimuthally and by range. Velocity and Spectrum Width data are combined azimuthally, only.
"> <Style FontSize="11" /> </Span> </Block> <Block> <Span Text="
"> <Style FontSize="11" /> </Span> </Block> <Block> <Span Text="When you are ready, proceed to the next slide to start the quiz."> <Style FontSize="11" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style LeadingMargin="0" FirstLineMargin="0" Justification="Left" ListLevel="1" LineSpacingRule="Multiple" LineSpacing="20" SpacingBefore="4.31999969" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Plain" Start="0" Color="#000000,00" BulletChar="•" BulletFont="Arial"> <BulletPicture Size="0x0" /> </ListStyle> </Style> <Span Text="This lesson is now complete. You can now move on to the next lesson in the course. Thank you for your time!"> <Style FontFamily="Open Sans" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" ForegroundColor="#444444" Elevation="Normal" DisplayCase="AsIs" LinkColor="#444444" /> </Span> </Block> </Content> </Document>