GISdevelopment.net ---> AARS ---> ACRS 1992 ---> Earth Environment The estimation and mapping of the grassland and desertification status in the UVS NUUR HOLLOW using satellite and round data D.Dash, G. Tsolmon, M. Badarch, Y. Bayarjargal National Remote Sensing Centre, Mongolia Khudaldaany Gydamj-5, Ulaanbaatar Abstract Uvs Nuur hollow is one of most important rangeland areas in Mongolia. This area is recently thereat ended by land degradation caused by overgrazing and the felling of trees for fuel. In this presentation reflects the results of application of remote sensing techniques for estimation and mapping of desertification process and grassland over Uvs Nuur hollow of Mongolia using Landsat TM and ground observation data. 1. Introduction Pasture vegetation resources of the most part of the territory of Mongolia have Gobi desert pasture, steppe pasture, and some of them can be used as cut grass for the fodder. Besides, some can also be used to collect medicinal plant. There exist problems in the development and utilization of pastures. For example the productivity of most of the pastures is low, pastures have been overgrazed universally, more pastures have deteriorated seriously. To utilize pasture vegetation resources particularly, in the Gobi desert and the steppe region of Mongolia, it is necessary to utilize rationally protect and improve them. Monglia has many head of animal. Therefore, the studies of the impact of scientific task for estimation of the ecological condition of the grassland and its change for the territory of Mongolia. Studies of the grassland type and it's environment using the satellite and ground data. Mongolia is facing the desertification process. The desertification problem in Mongolia has resulted from degradation of vegetation cover, wind erosion, water erosion, soil salination, overgrazing, cutting of the trees. (D. Dash, T. Baasan and others, 1991). The map of the desertification status covers only for round area of the Uvs Nuur lake. The climate and grassland are appearing vertically different distribution. The Study Area The Uvs Nuur hollow is a unique area, natural biosphere laboratory characterized by sharp biosphere processes {USSR Academy of Science, 1991 }. This hollow is situated on the frontier between Mongolia and Tuwa, Russia, approximately between 48-50 north and 91-99 east. The hollow locked by mountains. In the north it is closed by the Eastern and Western Tannu Ula mountain ridges and the Saglin upland, in the south-by the Bulnai Nuru and Khan Khukhei ridges and in the west-by the Tsagan Shibetu ridge and the Turgen Ula mountain mass of the Mongolian Altai. In the east the hollow is bordered by the watershed of the Delger Muren river basin. The hollow extends 160 km from north to south the 600 km from east to west. The salty Uvs Nuur lake is located in the western part of the hollow and gathers all the flowing waters. It serves as a small local sea which is 80x70 km large and 15m deep, the main water way are Tessiyn Gol and Naryin Gol. The average annual precipitation is about 150 mm. And there are several desert steppe and semi-desert area on the hollow bottom which lie nearly 1000 m above sea level. The study area includes the Landsat TM scene covering the western part of the Uvs Nuur hollow. The study area with about 3 million square km, covering the western part of Uvs Nuur hollow. 3. The methodology and data Some approaches by computer and ground data undertook were as follows: Selecting the best way for colour composition of different bands for the feature extraction. Selecting the most suitable scale of image enlargement. 3. Selecting the best classification schemes. Combining image processing with image interpretation. The map of the desertification status for the study areas compiled using the methodology of the Desert Institute, Academy of science of the Turkmen, ( N.G. Kharin, 1983 ) There were used the remote sensing data and field parasynchronic survey. Data from Landsat satellite was received in the middle of July, 1992. The field survey for estimation of the grassland type has been carried out in a fortnight after receiving the satellite data. For estimation of the desertification status were have sued the ground true data which was obtained in 1986 - 1980. Also were used the topographic maps with scale 1:100 000 and 1:200 000, 4. Results 1. Grassland. According to the classification standard of grassland and its realistic condition, grassland of the study area was classification into 6 districts, 61 associations and types. (Figure 1). Fig 1. The vegetation map of UVS NUUR HOLLOW The vegetation of western part of Uvs Nuur hollow is characterized by type of temperate belt: mountain tundra and forests. steppe and marshes, meadow and salines, brushowweds and areable lands. The vegetation cover of study area belong to two large different natural zones : the mountain region and the region of deserted steppe of drain less hollow deserts. In the mountain area, there is brown soil which is related to mountains and dry steppe. The main content of grassland for the tundra ) above 2900 m ) of the mountain area are Kobresia bellardii. Carex obtusata, Cladina Stellaris, Pleurozium Schreberii, Festuca altaica and Hedysarum alpinum. The main content of the grassland of dry steppe ( above the 1700m _ of the mountain area are Festuca lenensis, Buplerium multinerve and Leontopodium leontopoides. The average grassland productivity of the above mentioned area was 2.0 Cent. per hectare. In the plaint area, there are soft brown and light-coloured soils which related to steppe and desert steppe. The main contents of the grassland are Stipa krylovii, Poa atthenuata, Koeleria gracilas, Aster altaica, Buplerum vicaule, Artemisia frigida ( for the slopes of mountains ) and Stipa glareosa, Ahabasis brevifolio, Nanophyton erinaceum, Caragana bungei, Artemisia frigida, and Artemisia glauca ( for the valley territories, for example valley between the Uvs Nuur lake and Khan Khukhei and Tsagan Shibetu). The Territory around Uvs Nuur belongs to the desert steppe and the desert. There are Nanophyton erinaceum, Anabasis brevifolio, Artemisisa caespitoso, A. anethifolia and A. Schisvhkinii. In the Territory of rivers and low land, there are the main contents of grassland are Salex caspica, Populis pilosa, Caragana bungei, C. spinoso, Pragmites communis, Calamagrostis landsdorffi, Jris tenufolio, Lasiagrostis splendens, Carex discessa, C. dichroa and Chenopodium frutescens. The average productivity of the grassland of the plaint area was 3.0 Cent. per hectare. 2. Desertification. To combat desertification we need an initial information on the status of desert environment. For this purpose we had to use the status of desert environment. For this purpose we had to use two kinds of observation system such as surface and space. An expansion of the surface observation network into unpopulated desert areas would take long time and it ism,t economical. Also it would impact unfavorably on the country's limited human resources base. The advent of remote sensing data offers a solution of this information gap. These remarks are to stress the importance of remote , sensing data application technology for the desertification studies in Mongolia. So we have made an attempt to use stellite and ground data application technology for the desertification studies in Mongilia. So we have made an attempt tification process on the example of Uvs Nuur hollow. But we did not estimate the desertification process for the mountain area. The present desertification status of the Uvs Nuur hollow with scale 1:750 000 is presented in Figure 2. This figure shows that the Uvs Nuur hollow can be divided into 5 desertification. classes, namely: 1. No desertification, 2. Slight desertification, 3. Moderate desertification, 4. Severe desertification, 5. Very severe desertification. These desertification classes are well recognized on the colour satellite images. The marshes of rivers and some parts of the study area has not been deserted. Slight and moderate desertification belong to the slopes of the mountain area, for example, the slopes of Khan Khukhei, Kharikhraa and Turgen ridge. The sand region and settlement are threatened by severe and very severe desertification. Fig 2. The desertification types are indicated clearly on satellite image by the structure of the shape. On figure 2, showed 4 desertification types including the degradation of vegetation cover, wind erosion, water erosion and soil salinization. For the estimation of the desertification causes we have used the ground surveying data. In the desertification causes included the 4 aspects such as overgrazing, cutting of forests, development of agricultural lands and natural process. The causes of desertification are commonly anthropogenic, but that natural causes, resulting from climatic fluctuatuations, will be also important. Conclusion An important and effective method for estimation of the grassland type and present desertification status in Mongilia, sing technology with ground data. Desertification is currently one of the major global environmental concerns in Mongolia. Needs to expansion of application of remote sensing data for estimation and mapping of grassland condition and desertification status for the whole territory of Mongolia which is to be important for monitoring of natural resources and environment management of Mongolia. References T. Baasan, D. Dash, D. Enkhtaiwan, G. Tsolmon, N. Sarantuya, J. Natsag. Some results of the desertification studies , conducted in the aril areas of Mongilia. "Global change and Gobi desert" thesis of the presentations of the symbposum. Ulaanbaatar 1991. N.G. Kharin, N.T. Nechaeva, V.N. Nikoleave, T, Babayeva, L.G. Dobrin, A. Babaye, N.S. orlovskiy, A. Batyrov, I.P. Svintso. Methodological principles of desertification processes assessment and mapping. Arid lands of Turkmenistan taken as example. Ashkhabad, 1983.