October 20, 1809 UTC (click to enlarge)

October 23, 1835 UTC (click to enlarge)

Typhoon Nock-ten left four people dead and 1 missing this past week after hitting the northeastern coast of Taiwan. Most of the deaths were a result of landslides. The Tropical Rainfall Measuring Mission (TRMM) satellite has been collecting unique images and valuable data of tropical cyclones since its launch in November of 1997. TRMM captured these images of Nock-ten as it was approaching Taiwan.

According to the Joint Typhoon Warning Center, at the time of the first TRMM overpass at 18:09 UTC on the 20th of October 2004, Nock-ten was already a Category 2 typhoon packing winds of 95 knots (109 mph). The first image shows a horizontal map of the near surface rainfall intensity obtained from that overpass. Rain rates in the center part of the swath are from the TRMM Precipitation Radar or PR, while rain rates in the outer part of the swath are from the TRMM Microwave Imager or TMI. The rainfall rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). A well-defined eye is apparent in the center of the cloud mass. A substantial area of intense rain is just south of the center with rain rates on the order of 2 inches per hour (dark red areas). The overall rain area is asymmetrical with the bulk of the rain occurring west of the center including additional areas of heavy rain (red areas). At the time of this image, Nock-ten was already west-southwest of Guam and was moving northwest.

The second image was taken three days later on the 23rd of October at 18:35 UTC and shows Nock-ten near its peak intensity. The storm was now a Category 3 storm with maximum sustained winds estimated at 105 knots (121 mph) as it approached Taiwan. Nock-ten still has a well-defined eye with heavy (red) to intense (dark red) rain in the northern half of the eye wall. The bulk of the rain is now skewed to the north of the center. A large area of white cloudy wisps show the storm's outflow to the north. Nock-ten would remain a Category 3 typhoon for 1 more day before weaking to a Category 2 storm as it passed Taiwan. The system then quickly decayed into a tropical storm before dissipating just north of Taiwan. Nock-ten means bird in Laotian.

TRMM is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA).

Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).