| Land is a vital component of terrestrial ecosystems,and the impact of Land Use and Land Cover Change(LUCC)on hydro-meteorology has been an important topic in global climate change research.Recently,there have been significant changes in land use/cover patterns in Southwestern China,which have had profound impacts on local meteorological and surface processes.This study quantifies hydro-meteorological impacts under LUCC in the region,with the aim of protecting the local ecological environment,preventing hydrogeological hazards,and safeguarding agricultural production.This study systematically analyzed the effects of LUCC on meteorological factors and surface processes by using time series analysis and land surface model simulations.Firstly,based on various remote sensing data,the spatial and temporal changes of land use/cover and vegetation in the region were comprehensively investigated.Secondly,the effects of local urbanization on the spatial variations of meteorological factors such as temperature and precipitation were quantified in typical areas.Finally,the Noah-MP model was used to estimate the effects of land use/cover and vegetation changes on surface temperature,soil moisture and energy balance.The main contents and conclusions are as follows:(1)Based on remote sensing products such as land use/cover,Leaf Area Index(LAI),and Fractional Vegetation Cover(FVC),the spatial and temporal characteristics of land use/cover and vegetation change in recent decades were analyzed.The results showed that the main land use type was forest in the region,which covers about 45%of the region.The LUCC mainly shown a decrease in cropland area(decrease of about 8231 km~2)and an increase in built-up land(increase of about 10133 km~2)during 1980-2018.In addition,22.2%of the region underwent LUCC from 2001-2018.Meanwhile,most of the areas showed a significantly vegetation recovery in LAI and FVC.(2)Based on time series analysis,urbanization has magnified spatial variations of meteorological factors between local urban centers and surrounding areas over the past four decades.Specifically,Chengdu exhibited large spatial variations in meteorological factors during the rapid urbanization process.From 2000 to 2010,the differences between urban center and surrounding area,in terms of anomaly of air temperature and downward longwave radiation,and relative changes in wind speed and precipitation,were up to-0.69 K,-5.2 W/m~2,+22%,and+20%,respectively.However,from 2010 to 2018 these differences were reversed,with maximum of+0.78 K,+4.3 W/m~2,-17%,and-13%,respectively.The temporal and spatial differences of most meteorological factors in Chongqing were similar to those in Chengdu except for wind speed,which decreased first and then increased for the entire study period.Compared to Chengdu and Chongqing,LUCC in Kunming was more complicated,and the spatial variations of meteorological factors exhibited different patterns.This was probably due to large waterbody,which moderated the spatiotemporal evolution of local meteorological factors in this area.(3)Based on the simulation results of Noah-MP model,the effects of different land covers(2001,2018)and vegetation(LAI,FVC)on surface processes were compared.The results showed that under the influence of land cover type and vegetation changes,the surface temperature tended to decrease(0.1-0.4 K),while the latent heat tended to increase(0.5-2 W/m~2).The sensible heat variation was 0.6-1 W/m~2,and there was no significant change in albedo as well as soil moisture.In addition,soil moisture under land cover and vegetation changes in 2011 started to decrease in April,and the moisture decrease was more evident with increasing soil depth.However,due to the higher evapotranspiration under the vegetation change scenario,its effect on drought was more significant.This study is expected to support ecological construction,land management and sustainable development in the region. |
PDF Full Text Request