Shiro Ochi

Estimation of methane emission from West Siberian Lowland with sub-pixel land cover characterization

The West Siberian Lowland (WSL) is the worlds largest high-latitude wetland covering nearly 2/3 of western Siberia. At least half of this area consists of peatlands, which sequester atmospheric carbon in the form of undecomposed plant matter and it is presumed to be a source of methane gas. In this paper, firstly, an ASTER image near Noyabrsk mire was used to map six wetland ecosystems (red pine, white birch, bog, palsa, open water and bare soil) supplemented by field observation. Then spectral linear mixture analysis was performed between MODIS and ASTER data acquired on the same day. Secondly, field observations were scaled up with these different spatial resolution satellite data. Each of the wetland ecosystem coverage ratio in sub-pixel level was provided by the spectral linear mixture analysis. Field observation shows that the mean rate of CH/sub 4/ emission from bog and open water averaged 5.246 and 1.081 (mg CH/sub 4/ m/sup -2/ h/sup -1/) respectively. The methane emission from the area was estimated by multiplying these average methane emission rate and the area percentage of bog and open water in each pixel. Finally, the mean methane emission over MODIS coverage was estimated to be 1.864/spl times/10/sup 9/ g CH/sub 4/ day/sup -1/.

Accuracy assessment of geometric correction with Terra ASTER

ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is an imaging instrument that is flying on Terra, a satellite launched in December 1999 as part of NASAs Earth Observing System (EOS) . ASTER is a cooperative effort between NASA and Japans Ministry of Economy, Trade and Industry (METI) and the Earth Remote Sensing Data Analysis Center (ERSDAC) . ASTER data is distributed by HDF-EOS format, which has a very complicated data structure. It result in the difficulties of handling the data. However, that includes latitude and longitude values of footprints every 6km owing to the precise orbit tracing system with the star tracker. Precise geometric correction is one of the most difficult and indispensable process in remote sensing data. In this study, firstly, a free software is developed to achieve map projection conversion from UTM to plate carriee coordinate with ASTER data in HDF-EOS format. Secondly, map projection conversion is applied to sixteen scenes of ASTER data over Japan Island. Thirdly, accuracy of system geometric correction is evaluated with the castal lines and administrative boundary lines in vector format by visual interpretation. As a result, the root mean square geometric error is 79.2m in North West direction.

Report on Error Verification of Handy-GPS and Its Practical Utilization

With the expansion of GPS users, various types of GPS have appeared in the market. Accuracy is very much required for precise surveying, whereas cost performance is more important for many purposes such as car navigation system, field check investigation, etc. The accuracy of “Germin GPS-38”, a handy GPS marketed for recreational use, is examined in this paper. The error ranges for X (longitude), Y (latitude) and Z (altitude) direction are respectively-38m to +52m, -130m to +74m, and -289m to +71m by single GPS. In order to improve the accuracy, we found that the pseudo-differential method is effective. The error ranges of X, Y, Z direction changed to -40m to +49m, -31m to +33m and -66m to +46m respectively. By averaging 10 minutes data at the same point with pseudo-differential method, 14m distance error in X-Y plain is expected, which is acceptable for ground truth investigation for Remote Sensing data.