The Community Satellite Processing Package (CSPP) Polar2grid package is being updated and amended. Polar2grid version 3.1 (coming soon to a computer near your desk!) will include the ability to create reprojected images of Aerosol Optical Depth (AOD) and Normalized Difference Vegetation Index (NDVI). The imagery above from AWIPS shows the NOAA-20 AOD near the Lone Rock fire in north-central Oregon. The large values of AOD within the smoke plume are obvious. AOD display values are capped at 1.

Normalized Difference Vegetation Index, shown below in a toggle outlines the region where the fire has been, as an orange region surrounded by yellow to the north and green to the south, with the fire burning to the southeast of the burnscar.

---

A zoomed-out toggle of True Color and AOD, below, shows a much large smoke plume (characterized by very large AOD values) over much of Idaho in addition to the smoke plumes from individual fires in the Pacific Northwest.

View only this post Read Less

GOES-18 True Color imagery (from the CSPP Geosphere website) shows the growth of the Lone Rock fire burn scar over rural north-central Oregon (note the Columbia River at the top of the imagery) from 13 July 2024 (when the fire started in Gilliam County) to 17 July 2024. Careful examination of the True Color imagery shows a fire signal (in the form of a smoke plume) first appearing at 2206 UTC on 13 July 2024. How did NGFS — the Next Generation Fire System — alerts handle this event?

GOES-18 Band 7 shortwave infrared (3.9 µm) imagery, below, from the NGFS Real Earth instance shows 5-minute time steps before the time of the fire. It’s very difficult to determine the fire location from the Band 7 imagery alone. (Important: these GOES data are terrain-corrected; that is, the effects of parallax on the satellite detections have been removed. Thus, the actual location of the satellite pixels where fires are detected is defined with greater precision after applying terrain correction. This blog post (thanks Bill Line!) discusses parallax in surface features).

The NGFS Microphysics RGB (Quick Guide) below, for the same times as the Band 7 imagery above, shows a color change as the fire develops.

A feature of the Real Earth instance for NGFS is that the probe gives you information about the fire, as shown below. The Fire Radiative Power is shown, and the outline color of the pixel is a function of that number — note it changes from orange to red during the animation as the fire intensifies.

The NGFS Alerts Dashboard will continue to detect a fire after it has started (although Alerts are most useful for initial fire detections), as shown below in a screen shot from just before 1400 UTC on 18 July 2024. There are five alerts present for the Lone Rock fire — that has moved into Morrow County by that time — shown in grey. These alerts are labeled as being part of the Lone Rock fire because the fire was known at the time. These alerts are associated with new satellite pixels into which the fire has spread. They can also be due to fires flaring up again after a quiescent period.

Satellite Imagery from one of those alerts is shown below, and I’ve chosen the Day Cloud Fire RGB because it highlights the burn scar that is apparent in the Geosphere True Color imagery above. Recall that the pixels at this website can be queried to determine land surface features — that is shown in the stepped toggle below. The fire at this time was burning in a region of vegetation that included grassland, chapparal and forests.

The CIMSS NGFS website is here. Note that not all functionality shown in this blog post is publicly available.

View only this post Read Less

Day Cloud Phase Distinction imagery, above, from the GOES-16 CONUS Sector, shows the development of convection along the southern tier of counties in Wisconsin. LightningCast probabilities (the probability that a GLM observation will occur within the next 60 minutes) start to ramp up shortly after 1800 UTC, a 10% contour appears at 1826 UTC (in Rock County over southern Wisconsin), a 50% contour at 1851 UTC. The first GLM observation occurred between 1906 and 1911 UTC, meaning a lead time of more than 20 minutes from the appearance of the 50% contour.

Nexrad reflectivity for this time (downloaded from this site) is shown below. Note in particular that radar echoes did not occur until around 1806 UTC (here’s a toggle showing the radar at 1801 and 1806) — but LightningCast values started to increase around 1751 UTC. LightningCast is suggesting something might happen before a signal appears on radar. The interaction between the east-west line of convection over southern Wisconsins and the lake breeze front propagating inland also deserves mention!

LightningCast Probabilities are available at this RealEarth instance. One of the features at that site is the Aviation Lightning Dashboard, available at all airports within the USA (and some outside of the USA). The readout for the Rock County airport (KJVL) is shown below.

View only this post Read Less

Geo2grid software was used to create the three true-color animations below, using GOES-16 Full-Disk Level-1b Radiance data over the tropical Atlantic. ABI gives a vivid representation of the cloud patterns associated with a tropical wave developing (near 35^oW on 27 June, near 40^oW on 28 June, and approaching 50^oW on 29 June). The storm was declared a tropical depression at 2100 UTC on 28 June and was hurricane Beryl starting at 2100 UTC on 29 June (The archive of NHC advisories is here).

The geo2grid commands to create the GOES imagery are shown below. Three different domains are chosen, then the geo2grid commands to create true color imagery (-p true_color) on the defined grids (ATLTROP1, ATLTROP2 and ATLTROP3) are created, and coastlines and latitude/longitude lines are added. Image Magick was then used to annotate the imagery and create the animation.

./p2g_grid_helper.sh ATLTROP1 -30.0 8.0 2000 -2000 1760 760 > ATLTROP1.yaml
./p2g_grid_helper.sh ATLTROP2 -45.0 8.0 2000 -2000 1760 760 > ATLTROP2.yaml
./p2g_grid_helper.sh ATLTROP3 -50.0 10.0 2000 -2000 1760 760 > ATLTROP3.yaml
for k in 1000 1010 1020 1030 1040 1050 1100 1110 1120 1130 1140 1150 1200 1210 1220 1230 1240 1250 1300 1310 1320 1330 1340 1350 1400 1410 1420 1430 1440 1450 1500 1510 1520 1530 1540 1550 1600 1610 1620 1630 1640 1650 1700 1710 1720 1730 1740 1750 1800 1810 1820 1830 1840 1850 1900
do
./geo2grid.sh -r abi_l1b -w geotiff -p true_color -g ATLTROP1 --grid-configs ATLTROP1.yaml -f /path_to_abi_data/abi/L1b/RadF/*s2024179$k*
./geo2grid.sh -r abi_l1b -w geotiff -p true_color -g ATLTROP2 --grid-configs ATLTROP2.yaml -f /path_to_abi_data/abi/L1b/RadF/*s2024180$k*
./geo2grid.sh -r abi_l1b -w geotiff -p true_color -g ATLTROP3 --grid-configs ATLTROP3.yaml -f /path_to_abi_data/abi/L1b/RadF/*s2024181$k*
done
./add_coastlines.sh --add-coastlines --add-grid --grid-D 5.0 5.0 --grid-d 5.0 5.0 --grid-text-size 12 *ATLTROP1*.tif
./add_coastlines.sh --add-coastlines --add-grid --grid-D 5.0 5.0 --grid-d 5.0 5.0 --grid-text-size 12 *ATLTROP2*.tif
./add_coastlines.sh --add-coastlines --add-grid --grid-D 5.0 5.0 --grid-d 5.0 5.0 --grid-text-size 12 *ATLTROP3*.tif

---

GOES-16 and ABI give useful information about the clouds but the structures underneath the clouds — rain bands and moisture distributions — are vital for a complete understanding of how the atmosphere is behaving, especially for cases of developing tropical systems. JAXA’s GCOM-W1 satellite carries the AMSR-2 instrument that observes energy in the microwave part of the electromagnetic spectrum, and the data are available for download. This document below will walk you through the download procedure.

Once the data are available and downloaded to your system, use Polar2Grid to create imagery. For this case, I’ve chosen data swaths from June 27 (1453 UTC), June 28 (1536 UTC) and June 29 (1619 UTC). In this case we are focused on 89 GHz information; in the tropics, these data give information about deep convection because 89 GHz energy is strongly scattered by ice crystals as are found in deep convection. The polar2grid commands used to create imagery and to add a color enhancement that comes with polar2grid are listed below. Note that the grid definitions created for geo2grid, above, can be used for polar2grid. This makes it easy to overlay polar imagery on top of geo imagery, as shown below. A subsequent call to add_coastlines adds coastlines and latitude/longitude lines and a colorbar.

./polar2grid.sh -r amsr2_l1b -w geotiff -p btemp_89.0ah -g ATLTROP1 --grid-configs ./ATLTROP1.yaml -f ./AMSR2Data/GW1AM2_202406271453_085A_L1SGBTBR_2220220.h5

./polar2grid.sh -r amsr2_l1b -w geotiff -p btemp_89.0ah -g ATLTROP2 --grid-configs ./ATLTROP2.yaml -f ./AMSR2Data/GW1AM2_202406281536_092A_L1SGBTBR_2220220.h5

./polar2grid.sh -r amsr2_l1b -w geotiff -p btemp_89.0ah -g ATLTROP3 --grid-configs ./ATLTROP3.yaml -f ./AMSR2Data/GW1AM2_202406291619_099A_L1SGBTBR_2220220.h5

./add_colormap.sh ../colormaps/amsr2_89h.cmap gcom-w1_amsr2_btemp_89.0ah_20240629_161900_ATLTROP3.tif 
./add_colormap.sh ../colormaps/amsr2_89h.cmap gcom-w1_amsr2_btemp_89.0ah_20240628_153600_ATLTROP2.tif
./add_colormap.sh ../colormaps/amsr2_89h.cmap gcom-w1_amsr2_btemp_89.0ah_20240627_145300_ATLTROP1.tif

On 27 June, the daytime AMSR-2 overpass just missed (as sometimes happens!) the developing system, but there is information over the eastern 1/3rd of the tropical wave, and very little organization is present. One day later, on the 28th, the storm is sampled quite well, and cold cloud tops are apparent, but spiral banding is not. But the 29th, pronounced spiral banding is present and an eye is forming. (Click here to view the AMSR-2 imagery along at 0358 and 1619 UTC on 29 June).

---

At some time after the above post was published, the GCOM site entered a period of extended maintenance, scheduled to end in March of 2025. The pdf file below outlines how to access files. When you access the website https://gportal.jaxa.jp/gpr/, you’ll see an announcement that the website above is offline through at least March. However, JAXA has an Alternate Service for each satellite, including GCOM-W1. Once GCOM-W1 is selected, click on the G-Portal Repo, then standard, then GCOM-W1, and AMSR2, and L1b, then 2, then find the correct year/month combination. The month directory contains all that data available in that month, and it’s left to the user to determine the times needed. The SSEC/CIMSS Polar Orbit Track website is useful in that regard, as you can find the times when a Polar Orbiter satellite passed a particular point. That helps you download the correct files. In this case for Guam, the file names are GW1AM2_202411110314_205A_L1SGBTBR_2220220.h5 and GW1AM2_202411111536_100D_L1SGBTBR_2220220.h5 and Polar2Grid can create imagery from those files. Those are shown below.

View only this post Read Less