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Poster Session 2
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The study on biomass estimation in Mongolian Grassland
using satellite data and field measurement data
Table.1 Acquisition date and time of field measurement data in this study
| Date | Time | Number
of points |
| 1995/7/3 | 13:40-17:52 | 65 |
| 1996/8/7 | 12:03-13:53 | 100 |
| 1996/8/8 | 11:02-17:22 | 10 |
| 1996/8/14 | 15:44-17:30 | 100 |
| 1998/8/9 | 09:47-11:23 | 104 |
| 1998/8/9 | 11:39-13:21 | 105 |
| 1998/8/9 | 14:15-15:54 | 105 |
| 1998/8/9 | 16:15-17:52 | 93 |
| 1998/8/10 | 15:18-16:02 | 44 |
| 1998/8/10 | 12:15-14:01 | 109 |
| 1998/8/10 | 16:36-16:59 | 28 |
| 1998/8/11 | 12:04-13:15 | 55 |
| 1998/8/11 | 14:43-15:02 | 22 |
| 1998/8/2 1998/8/11 | 9:25 17:05 | 67 |
Table.2 NOAA AVHRR LAC in this study
| | Data | Time(GMT) |
| 1996's Data | 1996/7/30 | 5:51:58 |
| | 1696/7/31 | 5:39:36 |
| 1996/8/1 | 7:10:23 |
| 1996/8/2 | 5:18:00 |
| 1996/8/2 | 6:59:12 |
| 1998's Data | 1998/8/6 | 5:13:41 |
| | 1998/8/6 | 6:52:33 |
| 1998/8/6 | 8:35:12 |
| 1998/8/7 | 5:03:05 |
| 1998/8/7 | 8:23:34 |
| 1998/8/8 | 4:52:34 |
| 1998/8/8 | 6:30:36 |
| 1998/8/8 | 8:12:26 |
| 1998/8/9 | 6:19:39 |
| 1998/8/9 | 8:01:10 |
| 1998/8/10 | 6:08:36 |
| 1998/8/10 | 7:49:46 |
| 1998/8/11 | 5:57:35 |
| 1998/8/11 | 7:38:20 |
| 1998/8/12 | 5:46:40 |
| 1998/8/12 | 7:27:07 |
| 1998/8/13 | 5:35:55 |
| 1998/813 | 7:15:52 |
3.3 Satellite Data Processing
In this study, NOAA-14 AVHRR LAC data received at Ulaanbaatar in Mongolia was used. It is able to calculate reflectance from NOAA AVHRR LAC data ( Mather,1998). The accuracy of the reflectance is about 0.1%. NOAA/NESDIS (NOAA's National Environmental Satellite Data and Information Service) is opened for acquisition of the latest information of gain and offset for calibration. It is said that calibration coefficient is changeable for sensor deterioration, and so on ( Brest et al., 1992; Rao et al.,1994). In this study, the latest gain and offset was used every date of acquisition.
Geometric correction was conducted using automatic acquisition of GCPs. This method can generate GCP data automatically by matching the coastline data ( Shimoda et al.,1998, Hashimoto et al..,1993). In this study, residuals on image is less than 0.4 pixels, and map projection is Latitude/Longitude Grid system (WGS84) and resampling method is nearest neighbor.
Atmospheric correction was conducted by 6S code, which is focused on visible and near infra-red region ( Vermote et al., 1997 ). In this study, LUT method (Lei et al.,1998) was used. At first, LUT is calculated for each Sun-Target-Sensor geometry condition. GTOPO30 which has approx. 1km resolution is used as height above sea level . And high reliable data (AeroNet) is used as optical thickness (Optical thickness @550nm was re-calculated.), which was measured at Mandalgobi in Aug. of 1998. These data are obtained every day, and it is varied from 0.036 to 0.071. Therefore, in this study, 0.071 is used for 6Scode. Table.3 shows input parameters for 6S code.
Table.3 Input Parameters for 6S
| Atmospheric Model | Mid latitude Summer |
| Aerosole Model | Continental Model |
| Solar Zenith Angle | 0,10,20,30,40,50,60,70[deg] |
| Satellite Zenith Angle | 0,10,20,30,40,50,60,70[deg] |
| Relative Azimuth Angle | 0,20,40,60,80,100,120,140,160,180[deg] |
| Height avobe Sea Level | 0.0,0.5,1.0,1.5,2.0,2.5,3.0[km] |
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