The Grand Shangri-La(GSL) region has strong international tourist appeal. GSL has considerable international eco-tourist potential as well as being attractive for leisure, vacation, health, explorative, and scientific...The Grand Shangri-La(GSL) region has strong international tourist appeal. GSL has considerable international eco-tourist potential as well as being attractive for leisure, vacation, health, explorative, and scientific research activities in addition to high-end tourism experiences. These factors could promote the development of its regional tourism. GSL has been identified as a key area for tourism development in China. In this study, we investigated tourism climate conditions in GSL from 1980 to 2016 using a tourism climate index(TCI). We found that through global warming, the number of annual and monthly good-weather days, as assessed with the TCI, showed an increase over most of GSL;that trend was especially true for very good, excellent, and ideal days. The optimal travel period was May–October. We obtained the same result using cluster heat maps, in which we categorized 31 studied meteorological stations into eight types. However, heavy rainfall tended to occur during that optimal period, and it was concentrated at certain times. The annual total number of comfortable days greater than 300 was mainly located in southern GSL. We observed significant correlations between monthly and annual excellent and ideal days with latitude and elevation;in particular, we identified a significant nonlinear correlation between excellent(and ideal) days and elevation.展开更多
Through the analysis of the geographical features of the Shangri-La,the eco-tourism and environment-friendly land use patterns were proposed. And the significances of the mode of economic development in Shangri-La wer...Through the analysis of the geographical features of the Shangri-La,the eco-tourism and environment-friendly land use patterns were proposed. And the significances of the mode of economic development in Shangri-La were analyzed.展开更多
Southwest China is one of three major forest regions in China and plays an important role in carbon sequestration.Accurate estimations of changes in aboveground biomass are critical for understanding forest carbon cyc...Southwest China is one of three major forest regions in China and plays an important role in carbon sequestration.Accurate estimations of changes in aboveground biomass are critical for understanding forest carbon cycling and promoting climate change mitigation.Southwest China is characterized by complex topographic features and forest canopy structures,complicating methods for mapping aboveground biomass and its dynamics.The integration of continuous Landsat images and national forest inventory data provides an alternative approach to develop a long-term monitoring program of forest aboveground biomass dynamics.This study explores the development of a methodological framework using historical national forest inventory plot data and Landsat TM timeseries images.This method was formulated by comparing two parametric methods:Linear Regression for Multiple Independent Variables(MLR),and Partial Least Square Regression(PLSR);and two nonparametric methods:Random Forest(RF)and Gradient Boost Regression Tree(GBRT)based on the state of forest aboveground biomass and change models.The methodological framework mapped Pinus densata aboveground biomass and its changes over time in Shangri-la,Yunnan,China.Landsat images and national forest inventory data were acquired for 1987,1992,1997,2002 and 2007.The results show that:(1)correlation and homogeneity texture measures were able to characterize forest canopy structures,aboveground biomass and its dynamics;(2)GBRT and RF predicted Pinus densata aboveground biomass and its changes better than PLSR and MLR;(3)GBRT was the most reliable approach in the estimation of aboveground biomass and its changes;and,(4)the aboveground biomass change models showed a promising improvement of prediction accuracy.This study indicates that the combination of GBRT state and change models developed using temporal Landsat and national forest inventory data provides the potential for developing a methodological framework for the long-term mapping and monitoring program of forest aboveground biomass and its changes in Southwest China.展开更多
叶面积指数(leaf area index,LAI)是森林生态系统重要参数,如何以较小成本提升区域尺度的山地森林LAI的遥感估测精度,对于精确掌握森林LAI的情况和进一步了解森林生态系统有重要意义。本研究以星载激光雷达ICESAT-2/ATLAS为主要信息源,...叶面积指数(leaf area index,LAI)是森林生态系统重要参数,如何以较小成本提升区域尺度的山地森林LAI的遥感估测精度,对于精确掌握森林LAI的情况和进一步了解森林生态系统有重要意义。本研究以星载激光雷达ICESAT-2/ATLAS为主要信息源,以西南山地香格里拉市为研究区,基于随机森林回归(random forest,RF)遥感估测模型,结合地面51块LAI实测样地数据,在前期进行RF超参数优化基础上,采用决定系数、均方根误差、绝对平均误差和中位数绝对误差作为模型精度评价指标,对估测效果进行分析。结果表明:使用随机表面查找算法进行RF回归模型的超参数优化,能明显提升模型估测LAI精度。提取出的地面光斑特征参数在山地森林LAI估测中有较高的贡献度和极佳的效果,可用于区域尺度的山地森林物理结构参数LAI的估测。同时,利用随机表面查找算法优化后的RF回归模型,估测精度更高,估测结果与研究区森林分布现状吻合,具有一定普适性。最后,研究确定了使用ICESat-2/ATLAS数据产品估测LAI是可行的,能为星载激光雷达估测中大范围的LAI提供一定的参考。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 41571516, 41471448)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA19040503, XDA19040504)
文摘The Grand Shangri-La(GSL) region has strong international tourist appeal. GSL has considerable international eco-tourist potential as well as being attractive for leisure, vacation, health, explorative, and scientific research activities in addition to high-end tourism experiences. These factors could promote the development of its regional tourism. GSL has been identified as a key area for tourism development in China. In this study, we investigated tourism climate conditions in GSL from 1980 to 2016 using a tourism climate index(TCI). We found that through global warming, the number of annual and monthly good-weather days, as assessed with the TCI, showed an increase over most of GSL;that trend was especially true for very good, excellent, and ideal days. The optimal travel period was May–October. We obtained the same result using cluster heat maps, in which we categorized 31 studied meteorological stations into eight types. However, heavy rainfall tended to occur during that optimal period, and it was concentrated at certain times. The annual total number of comfortable days greater than 300 was mainly located in southern GSL. We observed significant correlations between monthly and annual excellent and ideal days with latitude and elevation;in particular, we identified a significant nonlinear correlation between excellent(and ideal) days and elevation.
基金Supported by Special Program of Social Career Development of Science and Technology Project in Yunnan Province(2010CA010)
文摘Through the analysis of the geographical features of the Shangri-La,the eco-tourism and environment-friendly land use patterns were proposed. And the significances of the mode of economic development in Shangri-La were analyzed.
基金supported by the State Forestry Administration of China under the national forestry commonwealth project grant#201404309the Expert Workstation of Academician Tang Shouzheng of Yunnan Province,the Yunnan provincial key project of Forestrythe Research Center of Kunming Forestry Information Engineering Technology
文摘Southwest China is one of three major forest regions in China and plays an important role in carbon sequestration.Accurate estimations of changes in aboveground biomass are critical for understanding forest carbon cycling and promoting climate change mitigation.Southwest China is characterized by complex topographic features and forest canopy structures,complicating methods for mapping aboveground biomass and its dynamics.The integration of continuous Landsat images and national forest inventory data provides an alternative approach to develop a long-term monitoring program of forest aboveground biomass dynamics.This study explores the development of a methodological framework using historical national forest inventory plot data and Landsat TM timeseries images.This method was formulated by comparing two parametric methods:Linear Regression for Multiple Independent Variables(MLR),and Partial Least Square Regression(PLSR);and two nonparametric methods:Random Forest(RF)and Gradient Boost Regression Tree(GBRT)based on the state of forest aboveground biomass and change models.The methodological framework mapped Pinus densata aboveground biomass and its changes over time in Shangri-la,Yunnan,China.Landsat images and national forest inventory data were acquired for 1987,1992,1997,2002 and 2007.The results show that:(1)correlation and homogeneity texture measures were able to characterize forest canopy structures,aboveground biomass and its dynamics;(2)GBRT and RF predicted Pinus densata aboveground biomass and its changes better than PLSR and MLR;(3)GBRT was the most reliable approach in the estimation of aboveground biomass and its changes;and,(4)the aboveground biomass change models showed a promising improvement of prediction accuracy.This study indicates that the combination of GBRT state and change models developed using temporal Landsat and national forest inventory data provides the potential for developing a methodological framework for the long-term mapping and monitoring program of forest aboveground biomass and its changes in Southwest China.
文摘叶面积指数(leaf area index,LAI)是森林生态系统重要参数,如何以较小成本提升区域尺度的山地森林LAI的遥感估测精度,对于精确掌握森林LAI的情况和进一步了解森林生态系统有重要意义。本研究以星载激光雷达ICESAT-2/ATLAS为主要信息源,以西南山地香格里拉市为研究区,基于随机森林回归(random forest,RF)遥感估测模型,结合地面51块LAI实测样地数据,在前期进行RF超参数优化基础上,采用决定系数、均方根误差、绝对平均误差和中位数绝对误差作为模型精度评价指标,对估测效果进行分析。结果表明:使用随机表面查找算法进行RF回归模型的超参数优化,能明显提升模型估测LAI精度。提取出的地面光斑特征参数在山地森林LAI估测中有较高的贡献度和极佳的效果,可用于区域尺度的山地森林物理结构参数LAI的估测。同时,利用随机表面查找算法优化后的RF回归模型,估测精度更高,估测结果与研究区森林分布现状吻合,具有一定普适性。最后,研究确定了使用ICESat-2/ATLAS数据产品估测LAI是可行的,能为星载激光雷达估测中大范围的LAI提供一定的参考。