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

Displaying NUCAPS data from CLASS

November 12th, 2014 |

NUCAPS data have been flowing into AWIPS 2 for months; in the recent past, these data started flowing into the NOAA CLASS data archive as well (click here for a tutorial on accessing the data). How can the NOAA CLASS output be displayed? This post will compare McIDAS-V plots to the data displayed using AWIPS-1, below.

GOES Sounder Total Column Ozone DPI Values Plotted with NAM 500-mb heights and NAM Pressure on the 1.5 PVU surface (click to enlarge)

GOES Sounder Total Column Ozone DPI Values Plotted with NAM 500-mb heights and NAM Pressure on the 1.5 PVU surface (click to enlarge)

Suomi NPP overflew the central United States at about 0850 UTC on 12 November, and ozone concentrations from the NUCAPS soundings at three different levels (~500, 300 and ~200 mb) are shown below. Note that the color scaling is not quite the same in the three plots as the range for each pressure level is different. Maxima in Ozone at all levels occur in the same region — the Dakotas — as indicated by the GOES Sounder Total Column Ozone DPI, above. NUCAPS soundings also show data in cloudy regions because microwave data from ATMS is used in the NUCAPS processing. Note that values at the edge of the color shading have been extrapolated outwards; values in western Nevada and Indiana, for example, are not from direct NUCAPS observations. This plot of 500-mb temperatures (that includes the actual values) shows the horizontal extent of data and the amount of interpolation at the edge.

Contours of Ozone Mixing Ratio (parts per billion) from NUCAPS Soundings at ~0848 UTC on 12 November 2014 (click to enlarge)

Contours of Ozone Mixing Ratio (parts per billion) from NUCAPS Soundings at ~0848 UTC on 12 November 2014 (click to enlarge)

Wildfire smoke over ice in Hudson Bay

July 28th, 2014 |
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

Large wildfires continued to burn during much of the month of July in the Northwest Territories of Canada, and McIDAS-X images of GOES-13 0.63 µm visible channel data on 28 July 2014 (above; click image to play animation) showed large amounts of smoke aloft streaming southwestward across the western and southwestern portion of Hudson Bay. This pattern of middle-tropospheric smoke transport was caused by the juxtaposition of a highly-amplified ridge of high pressure over central Canada and a deep area of low pressure over Quebec (500 hPa map). During the later part of the day, the clearing of patchy low clouds and the thinning of the smoke aloft revealed the presence of large ice floes over southwestern Hudson Bay. According to the Canadian Ice Service, this was thick first year ice from the previous winter season, with ice concentration values as high as 9-10/10s.

A Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image combination prepared using McIDAS-V (below; courtesy of Joleen Feltz, CIMSS) showed the variety of smoke, ice, and cloud formations over Hudson Bay at 18:45 UTC.

Suomi NPP VIIRS true-color RGB image

Suomi NPP VIIRS true-color RGB image

VIIRS nighttime signature of MV Sewol recovery operations site

April 22nd, 2014 |

A McIDAS-V image comparison of “before” (01 April) and “after” (22 April) Suomi NPP VIIRS 0.7 µm Day/Night Band data (above; courtesy of William Straka, SSEC/CIMSS) revealed the bright lights of the ongoing recovery operations associated with the sinking of the MV Sewol ferry on 16 April 2014 (Wikipedia). The bright illumination of the recovery site is located near the center of the 22 April image; the larger cluster of bright lights seen near the bottom of the 01 April image is likely a signature of extensive squid fishing operations. Numerous smaller and more dim lights from fishing boats can be seen on both images.

The ferry was taking a southbound route across the Yellow Sea, with a final destination of Jeju City (whose bright lights can be seen on the north edge of Jeju Island, at the bottom of the images).