Direct Broadcast imagery of a tropical system north of Guam

Images

The National Weather Service forecast office on Guam has a Direct Broadcast antenna, and CSPP software takes the downloaded signal and creates useful imagery. The example below shows JAXA’s GCOM AMSR-2 imagery at 36.5 and 89.0 GHz, and the structure of the low-level circulation (36.5 GHz) and upper-level clouds (89.0 GHz) are apparent. In the 36.5 GHz imagery, it’s likely the orange/red features are rain-producing clouds The 89.0 GHz imagery is coldest (yellow and red in that enhancement) where ice features are present because ice scatters 89.0 GHz energy very effectively. (The Joint Typhoon Warning Center has information on this storm here).

GCOM AMSR-2 images from the Guam DB antenna, 0339 UTC on 7 August 2024 (Click to enlarge)

Thanks to Douglas Schumacher, CIMSS, for forwarding along this imagery. But what if you don’t have the helpful Douglas to send you imagery? In that case, you can use Polar2Grid to create imagery from files downloaded from JAXA’s GPortal! That website allows a registered users (free registration!) to select specified data from a specific day over a specified region as shown in the succession of screen captures below.

Screens you’ll see as you choose GCOM AMSR-2 Level 1b data: Date Selection, Area Location, and Results (Click to enlarge)

The downloaded data can be processed with Polar2Grid software (using the -r amsr2_lib flag that reads AMSR-2 Level 1b data). This software can then produce imagery as shown below — looking very similar to the data from the Direct Broadcast antenna, but covering a larger area.

GCOM AMSR-2 images from the JAXA download site, 0315 UTC on 7 August 2024 (Click to enlarge)

A user can then get Himawari data (from, for example, an Amazon bit bucket) and use Geo2grid software to create imagery, shown below, with the same map projection as used for the Polar2grid imagery!

Himawari-9 Visible (Band 3, 0.64 µm) and Clean Window Infrared (Band 13, 10.4 µm) imagery, 0320 UTC on 7 August 2024 (Click to enlarge)

Combinations of Visible and Enhanced infrared imagery with the color-enhanced Microwave data are shown below. The combination of polar and geostationary satellite data yields a more complete understanding of the system.

Himawari-9 Visible Imagery (Band 3, 0.64 µm) at 0320 UTC overlain with GCOM-W1 AMSR-2 imagery (36.5 H and 89.0 H GHz) at 0315 UTC, 7 August 2024 (Click to enlarge)
Himawari-9 Infrared Imagery (Band 13, 10.4 µm) at 0320 UTC overlain with GCOM-W1 AMSR-2 imagery (36.5 H and 89.0 H GHz) at 0315 UTC, 7 August 2024 (Click to enlarge)

MIMIC Total Precipitable Water fields, below, show abundant moisture in the West Pacific including over Marianas Islands and Micronesia. A picture of rain on Guam from the WCM (Thanks Landon!) led me to investigate this system.

MIMIC Total Precipitable Water fields for the 24 hours ending 1900 UTC on 7 August 2024 (Click to enlarge)

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