| Based on the northeast of the northern area as the study area, based on the digital maps in 2010, TM remote sensing images and the CRU meteorological data in 2010,use of geographic information system for medium, analysis of land use change in the north of the northeast and drought conditions. Spatial analysis to explore the relationship and the influence of different land types to drought conditions. The results show that:(1)In 1950 s, forest land, farmland land, grassland and marsh dominated land use type accounted for 97.94% of the total area in the study are, the forest land area the largest, most widely distributed and film distribution, the region accounted for 40.7%; followed by arable land, swamp, meadow, respectively, the region accounted for 25.6%, 20.67%, 10.96%; land and other land area minimum waters, construction, proportion is minimal, dispersed distribution. 2010 s is given priority to with farmland land and forest land, including farmland land, the largest proportion of 42.77% of the total, are mainly distributed in the songnen plains and sanjiang plain area, forest land are mainly distributed in the north of heilongjiang province In central and southeast; Marsh and the grassland area is lesser, 6.8% of the total area of 6.8% respectively; The waters of the construction land and other land scattered distribution(2)Compared with 1950 s and 2010 s, between arable land, water area of construction land and other land, farmland land increased the most, followed the land for construction purposes. For the swamp, grassland and forest area is reduced. The main land use types in 1950s~2010s transformed between farmland, forest, grassland and marsh; the two land use types are the same, farmland, woodland area and continue to account for the largest proportion, both in the region accounted for 51.62% of the total area, and different land use type conversion in the area and the largest proportion of forest into farmland: the four types of forest into farmland, meadow into farmland, swamp, marsh turned into farmland.(3)Aridity index from 1961 to 2010 average of 1.118, slightly bigger than the precipitation potential evaporation; the most humid in 1991, the driest in 2001; base on spatial distribution, the western half of the study area for aridity index high value areas, the most dry, followed by other areas in eastern, relatively humid.(4)Aridity index from 1961 to 2010 in climate tendency rate for 0.016/10 a, showed a trend of greater volatility, and in 1975 by the wet dry mutation, mutations change from dry to wet in 1979. Based on space, index of aridity climate tendency rate between-0.006 and 0.036 every 10 years, increasing trend is dry in most area, especially southwest and central, climate tendency rate greater than 0.03/10 a in 1961~2010 years in the study area, where in the central and northeastern regions showing significant dry trend. The aridity climate tendency rate anomaly of study area shows: compared with the overall region, central and southwestern dry trend more and other areas, northwestern and southeastern dry trend in the study area is smaller than average overall situation.(5)Use three methods to extract dryness index of average and climate tendency rate is analyzed, analysis of land use types on dry degree of influence: according to the land use type extract extraction,the concentrated distribution area extraction and the concentrated distribution in region extraction. Conclusion: under the influence of various land use types, reducing effect to the dry degree of forest land, namely become wet, and other land types of dry degree are increased role, namely become dry, the more concentrated the class, the more obvious. Non-farmland into arable land, compared with the original continuous non-farmland, forest turn farmland, water turn arable land is more dry than continuous water dry, grassland into farmland, swamp into farmland, construction land to arable land, other land into farmland is more moister than sustainable grassland, swamp, construction land, other land. |
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