Cross-sections using gridded NUCAPS data in AWIPS

June 21st, 2022 |
NOAA-20 Day Night Band visible imagery (0.70) along with NUCAPS Sounding Availability points, ca. 19z on 21 June 2022 (Click to enlarge)

Gridded NUCAPS data, available from NOAA-20 data within AWIPS, can be used to construct cross-sections in AWIPS. The image above includes an editable baseline J-J’ (one of 10 different lines that can be used for data in AWIPS) from Minnesota into Indiana, roughly perpendicular to a line of broken cumulus over Wisconsin and Iowa.

Equivalent Potential Temperature along line J-J’ as indicated in imagery above (Click to enlarge)

The cross section of equivalent potential temperature, above, shows very warm temperatures over the southern portions of the cross section, with theta-e values around 350 K. Potential Instability, i.e., theta-e values decreasing with height, is widespread along the cross-section. The broken cloud field in the VIIRS imagery on top eventually did initiate convection, as shown in this radar capture from 0012 UTC on 22 June.

How do you create the cross-sections in AWIPS? Use the Volume Browser, as shown in the screen capture below. Select ‘Cross Section’ (vs. ‘Plan view’, for example) from the choices in the Volume Browser right next to ‘File’, ‘Edit’ and ‘Tools’, then choose ‘GriddedNUCAPS’ under ‘Sources’, and choose the correct Plane — as one of the Specified Lines you have previously moved in AWIPS; then choose the variable (possibilities are shown in the image; I chose Equiv Pot Temp).

Volume Browser presentation while creating Cross-Sections using gridded NUCAPS data (Click to enlarge)

Imagery in this blog was created using a cloud instance of AWIPS from the TOWR-S group within NOAA/NWS. Thank you!

Combining GOES-R and NUCAPS TPW fields in AWIPS

February 24th, 2022 |
GOES-16 Total Precipitable Water, 1900 UTC on 24 February 2022 (Click to enlarge)

Total Precipitable Water is a Level 2 Derived Product created from ABI (and ancillary) data (link to information on this product) The image above shows the product at 1900 UTC on 24 February 2022. It is immediately apparent that cloudy regions have no data! There are ways to fill in those gaps at different times of day.

NUCAPS thermodynamic profiles in AWIPS are derived from data from the CrIS (Cross-track Infrared Sounder) and ATMS (Advanced Technology Microwave Sounder) instruments on board NOAA-20. That thermodynamic data can be used to create fields of Total Precipitable Water, as shown below. Of course, the NUCAPS swath is limited geographically to the width of the CrIS and ATMS swaths, but values are created in clear and cloudy regions. Note that in AWIPS (which display system was used to create the imagery in this blog post) the gridded NUCAPS field has a different default color enhancement than what is shown below; create an AWIPS Procedure to load and enhance the swath with the same GOES-R enhancement used as a default in the image above.

Gridded NUCAPS estimates of Total Precipitable Water, 1900 UTC on 24 February 2022 (click to enlarge)

If you combine both the GOES-R TPW estimates with NUCAPS estimates at the same time, you will get enhanced coverage in regions where interesting weather might be happening (near gradients in TPW, for example) beneath cloud cover. NOAA-20 NUCAPS swaths occur every 90 minutes in the afternoon. moving east to west across the CONUS. Thus, at 1730 UTC, a NUCAPS TPW swath was available over the eastern part of the United States, and it could be combined with GOES-R values at that time, as shown at bottom. At 2030 UTC, a swath along the west coast (not showed) occurred. A similar set of swaths will occur east-to-west between about 0530 UTC and 1000 UTC in the morning.

GOES-16 and NUCAPS Total Precipitable Water, 1900 UTC 24 February 2022 (click to enlarge)
GOES-16 and NUCAPS Total Precipitable Water, 1730 UTC 24 February 2022 (click to enlarge)

AWIPS users can create a procedure to load gridded TPW fields in conjunction with GOES-R TPW fields, and use them as needed. AWIPS imagery in this blog post was created using the NOAA/NESDIS TOWR-S AWIPS Cloud Instance.

Adding gridded NUCAPS field to new AWIPS RGB loads

February 11th, 2022 |
GOES-16 Air Mass RGB loaded with Level 2 products: Clear Sky Mask, Lifted Index, CAPE and Total Precipitable Water, ca. 0816 UTC on 11 Feb 2022, with Gridded NUCAPS estimates of TPW at 0830 UTC (Click to enlarge)

This presentation from the TOWR-S Satellite Book Club details TOWR-S RPM 22 additions to AWIPS (additions spearheaded by Tim Schmit and Bill Line, both from NOAA/STAR) that add Level 2 product readouts to RGBs in AWIPS. Thus, for example, the Airmass RGB, above, is underlain by Level 2 products: Cloud Mask and Total Precipitable Water (TPW) and Level 2 Stability Indices (CAPE and Lifted Index). Those Level 2 products are all clear-sky only, however, so sampling in cloudy regions will not yield level 2 product information.

Adding Gridded NUCAPS fields (in the example above and below, total precipitable water has been added; one could also add CAPE and Lifted Index), is an effective way of including estimates of atmospheric thermodynamics in clear and cloudy regions that can then be sampled, as shown below with two sampling examples, one each in clear and cloudy skies. The sampling location is just northwest of the Clear Sky Mask value (i.e., the screen capture did not capture the cursor).

Sampled values over an Airmass RGB at 0816 UTC, including Gridded NUCAPS TPW at 0830 UTC, 11 February 2022 (Click to enlarge)

An efficient way to load these data in AWIPS is via a procedure. The augmented RGB loads are part of TOWR-S RPM 22.

Gridded NUCAPS fields are available in AWIPS

October 29th, 2019 |

NUCAPS Sounding Availability points from AWIPS, 1304 UTC on 29 October 2019, and the Temperature at 500 hPa at the same time (Click to enlarge)

Gridded NUCAPS fields (Here’s a NASA SpoRT VLab page on the product) are now available in AWIPS, effective with AWIPS Build 19.3.1. The imagery above includes a swath of NUCAPS points (called up via ‘NUCAPS Sounding Availability’) under the Satellite Tab, and the ‘S-NPP and NOAA-20’ choice there (even though, at present, only NOAA-20 NUCAPS profiles are supplied to AWIPS). A ‘Gridded NUCAPS’ choice is available right about the NUCAPS Sounding Availability, and this allows a user to choose Temperature, Dewpoint Temperature, Equivalent Potential Temperature, Lapse Rates (and more!) at different standard mandatory pressure levels (or layers, for Lapse Rates). Interpolation in the vertical has moved the native NUCAPS pressure levels (mentioned here) to standard pressure levels.

The plot above also shows the temperature at 500 hPa for the same time, 1304 UTC.  Gridded NUCAPS fields do not cover the entire extent of the NUCAPS Sounding Availability plots.  In addition, values are present for all sounding color dot points — green, yellow and red — on the theory that a user can identify the bad data visually.

The animation below shows a series of gridded fields over northern Canada, covering much of the the Sounding Availability plot.  Because of the timestamps on these different grids, they do not all time match the swath of NUCAPS Sounding Availability points. On this day, the size of some of the fields produced was quite small.  The size of the gridded region is limited by computational resources on AWIPS, and the upper limit is 20 lines of NUCAPS soundings — 600 soundings total that are horizontally and vertically interpolated. The size is also affected by the order in which the soundings appear in AWIPS. If a small chunk (say, 7 lines of soundings) comes in, then that small chunk will be processed into a horizontal grid. It’s more common that grid sizes will be closer to what occurred at 1304 UTC.

Temperature at 500 mb from NUCAPS Soundings, 1304 – 1311 UTC on 29 October 2019 (Click to enlarge)

If you look in the Product Browser on AWIPS, you will find far more data than are available under the ‘Gridded NUCAPS’ menu under ‘NOAA-20 and S-NPP’ under the satellite tab.  (Here’s just a small sample!)  For example, you can plot Ozone estimates from NUCAPS, as shown below — loaded as a grid then converted to an image.  Expect the presentation of NUCAPS horizontal fields in AWIPS to evolve with time.  In the meantime, this is a valuable data set to determine (for example) the likelihood of snow v. rain based on the 925 Temperature and Dewpoint Depression.

AWIPS Product Browser showing Ozone Estimates at 1304 UTC on 29 October 2019 (Click to enlarge)

(Thanks to Dr. Emily Berndt, NASA SpoRT, for clarifying remarks. Any errors that remain are the author’s, however!  Imagery courtesy NWS MKX)