Midwest Derecho

August 10th, 2020 |

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the eastward progression of a Mesoscale Convective System (MCS) that produced a long swath of damaging winds (SPC Storm Reports) or derecho from eastern Nebraska to Indiana on 10 August 2020. The highest measured wind gust was 112 mph in eastern Iowa at 1755 UTC.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

In a comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC (below), the higher spatial resolution of the VIIRS instrument detected infrared brightness temperatures as cold as -84ºC, compared to -76ºC with GOES-16 (the same color enhancement is applied to both images). The northwest parallax offset associated with GOES-16 imagery at this location was also evident.

Comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC [click to enlarge]

Comparison of Infrared Window images from Suomi NPP (11.45 µm) and GOES-16 (10.35 µm) at 1931 UTC [click to enlarge]

GOES-16 Visible/Infrared Sandwich Red-Green-Blue (RGB) and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports, is shown below. The probability contours are produced from a deep-learning algorithm used to identify patterns in ABI and GLM imagery that correspond to intense convection. It is trained to highlight strong convection as humans would identify it. Work is ongoing to incorporate this storm-top information into NOAA/CIMSS ProbSevere.

GOES-16 Visible/Infrared Sandwich RGB and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports (credit: John Cintineo, CIMSS) [click to play animation | MP4]

GOES-16 Visible/Infrared Sandwich RGB and “Clean” Infrared Window (10.35 µm) images, with “probability of intense convection” contours and SPC Storm Reports (credit: John Cintineo, CIMSS) [click to play animation | MP4]

A comparison of Terra MODIS True Color RGB images (source) from before (28 July) and after (11 August) the derecho (below) revealed very large swaths of wind-damaged crops (lighter shades of green) across Iowa. It is estimated that around 10 million acres of corn and soybean crops were flattened by the strong winds.

Comparison of before (28 July) / after (11 August) Terra MODIS True Color RGB images centered over Iowa [click to enlarge]

Comparison of before (28 July) / after (11 August) Terra MODIS True Color RGB images centered over Iowa [click to enlarge]

A toggle between VIIRS True Color RGB images from Suomi NPP and NOAA-20 visualized using RealEarth (below) also displayed the crop damage swath.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 -- with and without map labels [click to enlarge]

VIIRS True Color RGB images from Suomi NPP and NOAA-20 — with and without map labels [click to enlarge]

Shown below is a before/after (28 July/11 August) comparison of VIIRS Day/Night Band (DNB) imagery (source), where many of the areas across Iowa that suffered significant power outages — appearing darker (due to a lack of city lights) on the nighttime DNB images — corresponded to the large swaths of crop damage seen on the 11 August MODIS True Color image. Around 550,000 households lost power across the state.

VIIRS Day/Night Band (0.7 µm) images on 28 July and 11 August, along with a MODIS True Color RGB image on 11 August [click to enlarge]

VIIRS Day/Night Band (0.7 µm) images on 28 July and 11 August, along with a MODIS True Color RGB image on 11 August [click to enlarge]

Even 2 days later (on 12 August), many customers remained without power across Iowa (below), especially in Marshall County (where peak winds of 106 mph were recorded), Tama County (where peak winds of 90 mph were recorded) and Linn County (where peak winds of 112 mph were recorded).

Iowa counties with power outages on 12 August [click to enlarge]

Iowa counties with power outages on 12 August [click to enlarge]


Mount Sinabung eruption in Indonesia

August 10th, 2020 |

Himawari-8 True Color RGB images [click to play animation | MP4]

Himawari-8 True Color RGB images [click to play animation | MP4]

JMA Himawari-8 True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) displayed the gray to tan hues of a narrow west-to-east oriented volcanic ash cloud following an eruption of Mount Sinabung on 10 August 2020.

A sequence of Terra MODIS False Color RGB, Ash Probability, Ash Loading, Ash Height and Ash Effective Radius products from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) showed various characteristics of the ash plume at 0415 UTC.

Terra MODIS False Color RGB, Ash Probability, Ash Loading, Ash Height and Ash Effective Radius [click to enlarge]

Terra MODIS False Color RGB, Ash Probability, Ash Loading, Ash Height and Ash Effective Radius [click to enlarge]

A plot of 00 UTC rawinsonde data from Medan (below) helped to explain the different ash height and ash transport characteristics — the higher-altitude portion of the ash plume was transported westward by easterly flow above the 500 hPa (5.9 km) level, while the lower-altitude portion moved eastward due to westerly winds below 500 hPa.

Plot of 00 UTC rawinsonde data from Medan, Indonesia [click to enlarge]

Plot of 00 UTC rawinsonde data from Medan, Indonesia [click to enlarge]

Using Polar2Grid software to display historical MODIS data

May 19th, 2020 |

Terra MODIS Bands 2 (0.86 µm), 6 (1.62 µm) and 26 (1.38 µm) from 28 January 2004 (Click to enlarge)

The satellites Terra (launched in 1999) and Aqua (launched in 2002) both carry the Moderate-Resolution Imaging Spectroradiometer (MODIS) instrument, an imager with 26 channels at wavelengths that range from 0.41 µm to 14.1 µm. There are simple ways to create useful imagery with this historical data with Polar2Grid software that was developed at CIMSS as part of the Community Satellite Software Package (CSPP). This blog post will show you how to create imagery as shown above (0.86 µm, 1.62 µm and 1.38 µm) over Mt. Everest on 28 January 2004.  (Similar imagery from 29 January 2004:  0.86 µm, 1.62 µm, 1.38 µm, or toggles between 28/29 January at 0.86 µm, 1.62 µm and 1.38 µm)

The self-contained Polar2Grid software package can be downloaded from this link. (You may have to register your email address before accessing the site; registration is free). Once on the website, scroll down to find “Polar2Grid V2.3 Reprojection Software for Linux” (note that the version number will occasionally increment!) and download the gzipped tarfile. You should also download the documentation (it’s a pdf file) at that site. This will tell you what to do before you can successfully run the software: for example, the POLAR2GRID_HOME variable must be set:
export POLAR2GRID_HOME=/path/to/softwarebundle.

Next, order archived MODIS data. These data are available at the NASA LAADS (Level-1 and Atmosphere Archive and Distribution System) DAAC (Distributed Active Archive Center) at this link. If you click on ‘Find Data’ at that website, a long list of possible products will be displayed. MODIS data that are compatible with Polar2Grid are Level 1b Calibrated Radiances: MOD02 files, and for this example I chose 1-km and half-kilometer resolution (that is, MOD021KM, MOD02HKM). Geolocation files (MOD03) must also be selected.

Polar2Grid includes software to create a grid onto which the data will be projected; for the example above, I first ran the Polar2Grid script ./p2g_grid_helper.sh asia 87.0 28.0 500 -500 6000 6000 > myasiagrids.txt.

This creates a grid centered at 28 N, 87 E (west longitudes are negative) with a 500-m grid spacing in both x- and y-directions; the grid has a size of 6000×6000. If you don’t create a grid, the satellite data are placed on the native satellite grid, a grid that changes from day to day for a polar orbiter.

Once the MODIS data has been placed on your local machine, you are ready to use Polar2Grid to query what products can be created using this command

./polar2grid.sh modis gtiff --list-products -f /data-hdd/AckFriendData/MODIS/MOD02_03/day028/;

the -f flag identifies the directory holding the MODIS data and modis gtiff identifies the data type and output files to be created. The result of this is a (sometimes lengthy) list of products that can be created given the input. The following command creates geotiff:

./polar2grid.sh modis gtiff -p vis02 vis06 vis26 --grid-configs /home/scottl/Polar2Grid/polar2grid_v_2_3/bin/myasiagrids.txt -g asia -f /data-hdd/AckFriendData/MODIS/MOD02_03/day028/

This command creates Bands 2, 6 and 26 GeoTiffs, and the data are placed on the ‘asia’ grid defined above (and placed in the myasiagrids.txt file). The grids created do not have georeferencing embedded within the image; that is added with the add_coastlines shell script:
./add_coastlines.sh --add-grid --add-borders --borders-resolution=f --borders-outline='red' terra_modis_vis06_20040129_031000_asia.tif

The add-grid flag inserts lat/lon lines; add-borders includes country borders (with the outline color defined, and the resolution specified; for more control flags, refer to the documentation).

Other CIMSS blog posts that discuss Polar2Grid software are here , here and here.

(Added: GOES-9 was observing this part of the World in early 2004. Visible animations for 28 January and 29 January are available — click the dates).

Eruption of the Taal Volcano in the Philippines

January 12th, 2020 |

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.4 µm, right) images [click to play animation | MP4]

The Taal Volcano erupted in the Philippines around 0850 UTC on 12 January 2020. JMA Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images (above) displayed the volcanic cloud during the initial 3 hours post-eruption. Note the presence of a pronounced “warm wake” (red enhancement) downwind (north) of the summit of Taal — this appeared to be an Above-Anvil Cirrus Plume (AACP), as seen in a toggle between the Visible and Infrared images at 1910 UTC (below).

Himawari-8 "Red" Visible (0.64 µm) and "Clean" Infrared Window (10.4 µm) images at 1910 UTC [click to enlarge]

Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images at 1910 UTC [click to enlarge]

The warmest Himawari-8 10.4 µm brightness temperatures within the Above-Anvil Cirrus Plume were around -60ºC (red enhancement), which corresponded to approximately 21 km on data from 3 rawinsonde sites in the Philippines (Legaspi, Mactan and Laoag) (below).

Plots of rawinsonde data from Legaspi, Mactan and Laoag in the Philippines [click to enlarge]

Plots of rawinsonde data from Legaspi, Mactan and Laoag in the Philippines [click to enlarge]

The TROPOMI detected SO2 at altitude of 20km on 13 January:


A longer animation of Himawari-8 Infrared imagery revealed the intermittent presence of the warm wake feature until about 1400 UTC. The coldest 10.4 µm cloud-top brightness temperature was -89.7ºC.

Himawari-8 "Clean" Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 “Clean” Infrared Window (10.4 µm) images [click to play animation | MP4]

A large-scale view of Himawari-8 Infrared images (below) showed that the volcanic cloud was advected a great distance north-northeastward.

Himawari-8 "Clean" Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 “Clean” Infrared Window (10.4 µm) images [click to play animation | MP4]

A toggle between NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (below) showed the volcanic cloud at 1649 UTC.

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1648 UTC (credit: William Straka, CIMSS) [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1648 UTC (credit: William Straka, CIMSS) [click to enlarge]

In a sequence of Split Window Difference (11-12 µm) images (Terra MODIS, NOAA-20 VIIRS and Suomi NPP VIIRS) from the NOAA/CIMSS Volcanic Cloud Monitoring site (below), there was only a subtle ash signature (blue enhancement) immediately downwind of the Taal summit — due to the large amount of ice within the upper portion of the volcanic cloud, the infrared spectral ash signature was significantly masked.

Split Window Difference (11-12 um) images from Terra MODIS, NOAA-20 VIIRS and Suomi NPP VIIRS [click to enlarge]

Split Window Difference (11-12 µm) images from Terra MODIS, NOAA-20 VIIRS and Suomi NPP VIIRS [click to enlarge]

Of interest was the fact that Manila International Airport (RPLL) reported a thunderstorm at 15 UTC — there was a large amount of lightning produced by Taal’s volcanic cloud.

===== 14 January Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

2 days after the eruption, the leading edge of Taal’s SO2-rich volcanic plume (brighter shades of yellow over areas of cold clouds) began to appear within the far western view of GOES-17 (GOES-West) Full Disk SO2 Red-Green-Blue (RGB) images (above), about 1000 miles southeast of Japan. There were also some thin filaments of SO2 (brighter shades of white over warm ocean areas) moving southward, about 1500 miles west of Hawai’i.