*************************************** More on ASTER data of Merapi Volcano *************************************** From: Michael Ramsey <mramsey+@xxxxxxxx> In my previous posting to the volcano listserv, I described the ASTER data collected over Merapi on 06 June 2006. A cursory analysis was done on the visible/near infrared (VNIR) and thermal infrared (TIR) data for the day and night images. While here in Tokyo, Japan at the ASTER science team meeting, I have had time to further process the short wave infrared (SWIR) data in order to derive the high temperature information near the vent/dome. A new composite image has been posted here: http://ivis.eps.pitt.edu/data/merapi/day-SWIR3.pdf The image is the daytime VNIR data with the SWIR temperatures contoured near the summit. The maximum derived temperature (420 C) is slightly lower (and covering a smaller area) than those detected in earlier ASTER images. For example, on 30 May, the maximum derived temperature was 447 C, with 11 short wave infrared pixels in excess of 400 C, while only two pixels are greater than 400 C in these latest data. In a preliminary analysis of the plume, Vince Realmuto has determined that SO2 is at or below the detection limit for the ASTER TIR bands. A decorrelation stretch image is located here: http://ivis.eps.pitt.edu/data/merapi/day-SWIR3-dstr.pdf In this color combination, water/ice clouds tend to be indicated by the blue to cyan colors, ash is indicated by red colors, and SO2 would be indicated by yellow to orange. The plume is dominated by blue to magenta colors indicating a mix of ash and water vapor with low SO2. More analysis will continue on these and past ASTER data. In addition, ASTER will continue to image Merapi as often as possible during the ongoing volcanic crisis in Indonesia. Cheers, Mike +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Dr. Michael Ramsey, Associate Professor Dept. of Geology & Planetary Science, University of Pittsburgh 4107 O'Hara Street, room 200 SRCC Pittsburgh, PA 15260-3332, USA office: 412-624-8772; fax: 412-624-3914; IVIS Lab: 412-624-8773, IVIS Spectrometer Lab: 412-624-7874 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
