Atmos. Chem. Phys., 17, 10709-10732, 2017
Yüklə 451,19 Kb. Pdf görüntüsü
|
- Bu səhifədəki naviqasiya:
- SEVIRI 11 µ m temperature, date: 21 May 2010, time: 19:00 UT -19.0 -18.5 -18.0 -17.5
- -17.5 -17.0 -16.5 -16.0 Longitude ( o ) 63.0
10716 F. Prata et al.: Separation of ash and SO 2 SEVIRI 11 µ m temperature, date: 21 May 2010, time: 19:00 UT -19.0 -18.5 -18.0 -17.5 -17.0 -16.5 -16.0 Longitude ( o ) 63.0 63.5 64.0 64.5 65.0 65.5 66.0 Latitide ( o ) Temperature (K) 250 252 254 256 258 260 262 264 266 268 270 SEVIRI 11 µm temperature, date: 21 May 2010, time: 19:15 UT -19.0 -18.5 -18.0 -17.5 -17.0 -16.5 -16.0 Longitude ( o ) 63.0 63.5 64.0 64.5 65.0 65.5 66.0 Latitide ( o ) 228 232 236 240 Temperature (K) 220 224 228 232 236 240 244 248 252 256 260 SEVIRI 11 µm temperature, date: 21 May 2010, time: 19:30 UT -19.0 -18.5 -18.0 -17.5 -17.0 -16.5 -16.0 Longitude ( o ) 63.0 63.5 64.0 64.5 65.0 65.5 66.0 Latitide ( o ) 228 232 236 240 240 Temperature (K) 220 224 228 232 236 240 244 248 252 256 260 SEVIRI 11 µm temperature, date: 21 May 2010, time: 19:45 UT -19.0 -18.5 -18.0 -17.5 -17.0 -16.5 -16.0 Longitude ( o ) 63.0 63.5 64.0 64.5 65.0 65.5 66.0 Latitide ( o ) 226 228 228 228 232 232 236 236 240 240 Temperature (K) 220 224 228 232 236 240 244 248 252 256 260 Figure 4. Close-up views of the 11 µm brightness temperatures from the SEVIRI instrument at 15 min intervals, starting at 19:00 UTC on 21 May 2011. Isolines (contours) of brightness temperatures are shown in white to highlight the location and expansion of the top of the column. The rapid plume rise may be interpreted by the change in extent of the cloud-top temperatures. There is no evidence of an eruption in the image at 19:00 UTC. The location of Grímsvötn is shown as a black triangle. 2. The layer was sulfate with some depolarization from ice particles (not very likely in the stratosphere). 3. The layer was sulfate with some depolarization from small ash particles (below the detection limit of AIRS). The last interpretation is certainly consistent with obser- vations of some small amounts of ash in the northern part of the plume (Prata and Rose, 2015). The colour ratios (χ ; see https://eosweb.larc.nasa. gov/PRODOCS/calipso/Quality_Summaries/CALIOP_ L2LayerProducts_3.01.html for more details of these parameters) are χ ∼ 1 for ash and χ ∼ 0.5 for SO 4 2−
showing a clear difference between these two aerosol layers. The ash layer shows considerable vertical structure, with thin layering evident below 3 km and a broader feature peaking ∼ 4.5 km. These data provide compelling evi- dence for ash and SO 2 (and SO 4 2− ) separation from the Grímsvötn eruption and also provide quantitative estimates of the height separation with a lower-troposphere ash cloud and a stratospheric gas and aerosol cloud. 4.3
SO 2 gas The satellite instruments used to retrieve SO 2 are also shown in Table 1. Details of the retrieval algorithms may be found in the papers by Prata and Bernardo (2007) for the AIRS, Atmos. Chem. Phys., 17, 10709–10732, 2017 www.atmos-chem-phys.net/17/10709/2017/ Yüklə 451,19 Kb. Dostları ilə paylaş:
|