The vegetation of mainland Southeast Asia is less known to science.This article introduces the studies up to now on the vegetation of mainland Southeast Asia(Indochina peninsula),and describes the main fo-rest vegetat...The vegetation of mainland Southeast Asia is less known to science.This article introduces the studies up to now on the vegetation of mainland Southeast Asia(Indochina peninsula),and describes the main fo-rest vegetation types based on fragmentary information and field visits.Seven main terraneous and wet land forest vegetation types,including coniferous forest,coniferous-broad-leaved mixed forest,tropical montane evergreen broad-leaved forest,tropical rain forest,tropical seasonal moist forest,tropical monsoon forest,and dry thorny thickets/woodland(savanna),are recognized.Of them,the coniferous forest includes two subtypes:temperate coniferous forest and tropical coniferous forest;the coniferous-broad-leaved mixed forest includes also two subtypes:warm temperate and temperate coniferous-broadleaved mixed forests;and the tropical rain forest includes four main vegetation subtypes:tropical lowland evergreen rain forest,tropical seasonal rain forest(tropical lowland semi-evergreen rain forest),tropical montane rain forest,and peat swamp forest.The study history of the vegetation in the region,its classification,physiognomic characteristics,and dominant species composition,are also concisely introduced.展开更多
The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR ...The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR data archive and provide new control point data for large-scale topographic mapping and geodetic surveying.However,the accuracy of the ATL 08 terrain estimates has not been fully evaluated on a large scale and in complex terrain conditions.This article aims to quantitatively assess the accuracy of ICESat-2 ATL 08 terrain estimates.Firstly,the ICESat-2 ATL 08 terrain estimates were compared with the high-precision airborne LiDAR digital terrain model(DTM),and impacts of acquisition time,vegetation cover type,terrain slope,and season change on the terrain estimation accuracy were analyzed.We get the following conclusions from the analysis:1)the mean and RMSE of the terrain estimates of day acquisitions are 0.22 m and 0.59 m higher than that of night acquisitions;2)the accuracy of the ATL 08 terrain estimates acquired in vegetated areas is lower than those in non-vegetated areas;3)the accuracy of the ATL 08 terrain estimates is inversely proportional to the slope,and the elevation error increases significantly when the terrain slope is larger than 30°;4)in the non-vegetation covered area,the accuracy of the ATL 08 terrain estimates of summer and winter acquisitions has no obvious discrepancy,but in vegetated area,the accuracy of winter acquisitions is significantly better than that of summer acquisitions.This research provides references for the selection and application of ICESat-2 data.展开更多
文摘The vegetation of mainland Southeast Asia is less known to science.This article introduces the studies up to now on the vegetation of mainland Southeast Asia(Indochina peninsula),and describes the main fo-rest vegetation types based on fragmentary information and field visits.Seven main terraneous and wet land forest vegetation types,including coniferous forest,coniferous-broad-leaved mixed forest,tropical montane evergreen broad-leaved forest,tropical rain forest,tropical seasonal moist forest,tropical monsoon forest,and dry thorny thickets/woodland(savanna),are recognized.Of them,the coniferous forest includes two subtypes:temperate coniferous forest and tropical coniferous forest;the coniferous-broad-leaved mixed forest includes also two subtypes:warm temperate and temperate coniferous-broadleaved mixed forests;and the tropical rain forest includes four main vegetation subtypes:tropical lowland evergreen rain forest,tropical seasonal rain forest(tropical lowland semi-evergreen rain forest),tropical montane rain forest,and peat swamp forest.The study history of the vegetation in the region,its classification,physiognomic characteristics,and dominant species composition,are also concisely introduced.
基金Projects(41820104005,41904004,42030112)supported by the National Natural Science Foundation of China。
文摘The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR data archive and provide new control point data for large-scale topographic mapping and geodetic surveying.However,the accuracy of the ATL 08 terrain estimates has not been fully evaluated on a large scale and in complex terrain conditions.This article aims to quantitatively assess the accuracy of ICESat-2 ATL 08 terrain estimates.Firstly,the ICESat-2 ATL 08 terrain estimates were compared with the high-precision airborne LiDAR digital terrain model(DTM),and impacts of acquisition time,vegetation cover type,terrain slope,and season change on the terrain estimation accuracy were analyzed.We get the following conclusions from the analysis:1)the mean and RMSE of the terrain estimates of day acquisitions are 0.22 m and 0.59 m higher than that of night acquisitions;2)the accuracy of the ATL 08 terrain estimates acquired in vegetated areas is lower than those in non-vegetated areas;3)the accuracy of the ATL 08 terrain estimates is inversely proportional to the slope,and the elevation error increases significantly when the terrain slope is larger than 30°;4)in the non-vegetation covered area,the accuracy of the ATL 08 terrain estimates of summer and winter acquisitions has no obvious discrepancy,but in vegetated area,the accuracy of winter acquisitions is significantly better than that of summer acquisitions.This research provides references for the selection and application of ICESat-2 data.
