Typhoon Dolphin approaches Guam

May 14th, 2015
Himawari-8 11.22 µm infrared channel images (click to play animation)

Himawari-8 11.22 µm infrared channel images (click to play animation)

The animation above (available here as an mp4, and here on YouTube) shows 11.22 µm infrared imagery at 2.5-minute time steps (bottom) and 10-minute time steps (top) from Himawari-8 on 14 May 2015. Category 2 intensity Typhoon Dolphin is approaching Guam, seen at the left edge of both panels in the frame. The 2.5-minute imagery gives a much better indication of the quick rise and decay of overshooting tops (IR brightness temperatures of the storm tops approach -95º C!). A 10-minute time step cannot fully resolve the evolution of these features. The 2.5-minute time step also better captures the divergent flow (and outward-propagating gravity waves) at the top of the central dense overcast. No eye was yet apparent in the infrared imagery, or on DMSP SSMI 85 GHz microwave imagery.

A similar animation from the previous day, 13 May, is shown here: gif, mp4, YouTube. The better organization of the storm on 14 May is readily apparent.

How high are the clouds in the Central Dense Overcast (CDO)? Cloud Heights are available from CLAVR-x (Clouds from AVHRR Extended). Data from Geostationary Satellites are processed and are available to download here. Values from COMS-1 and from MTSAT-2 (displayed with McIDAS-V) suggest maximum cloud heights near 55,500 feet.

The MIMIC Total Precipitable Water (TPW) product, below, showed that Typhoon Dolphin was able to tap rich moisture from the Intertropical Convergence Zone (ITCZ) during the 13-14 May period; TPW values within the tropical cyclone circulation were often in the 60-65 mm or 2.5-2.6 inch range (darker red color enhancement).

MIMIC Total Preciptable Water product (click to play animation)

MIMIC Total Preciptable Water product (click to play animation)

Visible Imagery from Himawari-8, just after sunrise on 15 May, show continuous development of short-lived overshooting tops to the east of Guam. More information on the storm is available at the CIMSS Tropical Cyclones site, the JMA Tropical Cyclone site and the Joint Typhoon Warning Center.

Himawari-8 0.6363 µm visible channel images (click to play animation)

Himawari-8 0.6363 µm visible channel images (click to play animation)

The nighttime glow of Hawaii’s Kilauwea volcano

April 28th, 2015
Himawari-8 3.9 µm shortwave IR images (click to play animation)

Himawari-8 3.9 µm shortwave IR images (click to play animation)

The Kilauwea Volcano on the Big Island of Hawai’i began erupting in March 2008 (blog post | USGS reference), and has been in a nearly continuous phase of activity since then. During the pre-dawn hours of 28 April 2015, thermal signatures of the Kilauwea summit lava lake and nearby lava flows could be seen on McIDAS-V images of 10-minute interval Himawari-8 3.9 µm shortwave IR images (above; click image to play animation). The dark black pixels represent the hottest IR brightness temperatures.

On the corresponding Himawari-8 2.3 µm near-IR channel images (below; click image to play animation), the clusters of bright white pixels represent the glow of the hot lava features.

Himawari-8 2.3 µm near-IR channel images (click to play animation)

Himawari-8 2.3 µm near-IR channel images (click to play animation)

A different view is provided by the polar-orbiting Suomi NPP satellite — a comparison of AWIPS II images of VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR data (below) revealed the locations of the hottest lava features (black to yellow to red color enhancement) at 11:40 UTC (1:40 am local time).

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 3.74 µm shortwave IR images

A longer animation using GOES-15 (GOES-West) 3.9 µm shortwave IR images (below; click image to play animation) showed considerable temporal fluctuation in the location and intensity of the hot lava pixels (black to yellow to red color enhancement). For the latest information on the Kilauea eruption, visit the Hawaiian Volcano Observatory.

GOES-15 3.9 µm shortwave IR images (click to play animation)

GOES-15 3.9 µm shortwave IR images (click to play animation)

Major sandstorm in the Arabian Peninsula

April 2nd, 2015
Visible satellite images and surface observations (click to play animation)

Visible satellite images and surface observations (click to play animation)

Visible satellite images from the SSEC RealEarth web map server (above; click image to play animation) revealed the hazy light gray signature of a major sandstorm that was advancing south-southeastward across the Arabian Peninsula on 02 April 2015. An Aqua MODIS true-color Red/Green/Blue (RGB) image (actual satellite overpass time was 10:20 UTC or 2:20 PM local time) is shown below — the dense cloud of airborne sand appeared as a lighter shade of tan.

Aqua MODIS true-color image

Aqua MODIS true-color image

A Suomi NPP VIIRS true-color image from the previous day (below) depicted the beginning phase of the sandstorm in the northern portion of Saudi Arabia, which consisted of a number of smaller plumes of blowing sand prior to consolidating into the large feature seen on 02 April.

Suomi NPP VIIRS true-color image (01 April)

Suomi NPP VIIRS true-color image (01 April)

The blowing sand reduced surface visibility to near zero at some locations, disrupting ground transportation, air traffic, and also closing schools. Visibility was reduced to 0.1 mile for several hours at Dubai International Airport (below), which is one of the world’s busiest in terms of volume of flights.

Time series of weather conditions at Dubai International Airport

Time series of weather conditions at Dubai International Airport

During the previous nighttime hours, McIDAS-V images of Suomi NPP VIIRS 0.7 µm Day/Night Band data (below; images courtesy of William Straka, SSEC) showed the arc-shaped leading edge of the sandstorm as it stretched from the United Arab Emirates across Saudi Arabia at 22:01 UTC or 1:01 AM local time. Since the Moon was in the Waxing Gibbous phase (at 98% of Full), it provided ample illumination for these “visible images at night”.

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Typhoon Maysak in the West Pacific Ocean

March 30th, 2015
Himawari-8 AHI 0.64 µm visible channel images (click to play animation)

Himawari-8 AHI 0.64 µm visible channel images (click to play animation)

McIDAS-V images of Himawari-8 AHI 0.64 µm visible channel data (above; click image to play animation; images courtesy of William Straka, SSEC) showed the evolution of Category 2 Typhoon Maysak over the West Pacific Ocean on 30 March 2015. A number of large convective bursts can be seen surrounding the eye, along with more subtle features such as transverse banding.

An 11:01 UTC MTSAT-2 10.8 µm IR image with an overlay of 11:11 UTC Metop ASCAT surface scatterometer winds from the CIMSS Tropical Cyclones site (below) revealed the wind field in the eastern semicircle of the tropical cyclone.

MTSAT-2 10.8 µm IR image with Metop ASCAT surface scatterometer winds

MTSAT-2 10.8 µm IR image with Metop ASCAT surface scatterometer winds

Several hours later, a comparison of a 19:01 UTC MTSAT-2 10.8 µm IR image with a 19:00 UTC DMSP SSMIS 85 GHz microwave image (below) showed that the microwave instrument was able to “see” through the clouds surrounding the eye to depict the larger size of the eyewall structure.

MTSAT-2 10.8 µm IR image + DMSP SSMIS 85 GHz microwave image

MTSAT-2 10.8 µm IR image + DMSP SSMIS 85 GHz microwave image

During the later hours of 30 March, Typhoon Maysak underwent a period of rapid intensification from a Category 2 to a Category 4 storm, as depicted on a plot of the Advanced Dvorak Technique (ADT) intensity estimate (below). Rapid intensification occurred as the tropical cyclone was moving over an area of relatively high ocean heat content.

Advanced Dvorak Technique (ADT) intensity estimate plot for Typhoon Maysak

Advanced Dvorak Technique (ADT) intensity estimate plot for Typhoon Maysak

MTSAT-2 10.8 µm IR channel images during this period of rapid intensification are shown below (click image to play animation).

MTSAT-2 10.8 µm IR images (click to play animation)

MTSAT-2 10.8 µm IR images (click to play animation)

The MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) depicted TPW values in excess of 60 mm or 2.36 inches (darker red color enhancement) associated with Maysak as the tropical cyclone moved between the islands of Guam (PGUM) and Yap (PTYA). Yap recorded over 4 inches of rainfall.

MIMIC Total Precipitable Water product (click to play animation)

MIMIC Total Precipitable Water product (click to play animation)

31 March 2015 Update: Maysak intensified to a Category 5 Super Typhoon (ADT plot). Full-resolution visible imagery from Himawari-8 AHI is shown below; a faster animation is available here. A number of mesovortices could be seen within the eye of Maysak; these mesovortices were also evident in photos of the eye of the typhoon taken by an astronaut on the International Space Station, as posted on Twitter here and here.

Himawari-8 AHI 0.64 µm visible channel images (click to play animation)

Himawari-8 AHI 0.64 µm visible channel images (click to play animation)

Images from all 16 channels from the Himawari-8 AHI can be combined into one animation, showing the different information provided by each of the spectral bands — such an animation is shown below, using data from 0600 UTC on 31 March 2015. The Infrared data is shown at full (2-km) resolution; Visible/near Infrared imagery is scaled down by a factor of 2 (0.46 µm, 0.51 µm, 0.85 µm) or by a factor of 4 (0.64 µm). A similar animation, but without annotation or color enhancement, is available here.

Himawari-8 AHI images for all 16 channels at 0600 UTC (click to enlarge)

Himawari-8 AHI images for all 16 channels at 0600 UTC (click to enlarge)

Maysak had remained in an environment of relatively low deep-layer wind shear (below; click image to play animation), which was favorable for its trend of continued intensification.

MTSAT-2 10.8 µm IR channel images, with deep-layer wind shear (click to play animation)

MTSAT-2 10.8 µm IR channel images, with deep-layer wind shear (click to play animation)

However, in a comparison of MTSAT-2 10.8 µm IR channel and TRMM TMI 85 GHz microwave images around 14 UTC (below), it can be seen that the microwave image indicated that an eyewall replacement cycle might be underway (which would suggest a subsequent decrease in the typhoon’s intensity within the coming hours). This was supported by the ADT intensity estimate plot, which dropped the intensity of Maysak just below 140 knots after 18 UTC on 31 March.

MTSAT-2 10.7 µm IR image and TRMM TMI 85 GHz microwave image

MTSAT-2 10.7 µm IR image and TRMM TMI 85 GHz microwave image

01 April Update: A nighttime comparison of Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR images at 16:58 UTC on 01 April (below; images courtesy of William Straka, SSEC) showed the eye of Typhoon Maysak after it had weakened to a Category 4 storm.

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images