A package to manipulate GCM data from NEX-GDDP dataset
NEX-GDDP数据集介绍：
The NEX-GDDP dataset includes downscaled projections for RCP 4.5 and RCP 8.5 from the 21 models and scenarios for which daily scenarios were produced and distributed under CMIP5. Each of the climate projections includes daily maximum temperature, minimum temperature, and precipitation for the periods from 1950 through 2100. The spatial coverage encompasses the entire earth at a resolution of 0.25 degrees (~25 km x 25 km).For further information on the methods and contents of the data refer to the technical note on the NEX-GDDP dataset. GCM_download_data（）Download and reshape netCDF files from NASA's NEX-GDDP
源代码：https://rdrr.io/github/hllauca/RClimChange/src/R/GCM_download_data.R
GCM_download_data(FileURLs, Variable = "pr", RangeLat, RangeLon)
FileURLs
Text file with NEX-GDDP URLs to be downloaded.
下载URL文件：
https://drive.google.com/open?id=1yr3iDTPyPds6QZy_exW7COkEUKmzqnc6
Variable
Variable of interest to be downloaded (pr, tasmax or tasmin). 'pr' as default.
RangeLat
Range (min,max) of latitudes to subset data.
RangeLon
Range (min,max) of longitudes to subset data.
Examples：
install.packages("devtools")
devtools::install_github("hllauca/RClimChange")
library(RClimChange)
setwd("D:/NEX-GDDP_URLs/") #储存数据集URL信息文件夹
GCM_download_data(FileURLs='pr_rcp4.5text.txt',
Variable='pr',
RangeLat=c(30.2,34.5),
RangeLon=c(105.5,112.5)) #研究区
GCM_extract_region（）
读取GCM子集并使用netCDF GCM的文件构建一个5D[lon,lat,day,year,model]数组
GCM_extract_region(Path.GCM, Region, Var)
Path.GCM
Directory where GCM netCDF files are located.
Region
Lat/Lon ranges for subsetting data (MinLon, MaxLon, MinLat, MaxLat).
Var
Variable of intereset to be extracted (Pp, Tmax or Tmin).
Value：
5D array [lon,lat,day,year,model] with GCM subset data.
GCM_spatial_down（）
Extract a downscaled GCM data for a point of interest
GCM_spatial_down(Input, RegLon, RegLat, XYcoords, YearIni, b = 2)
Input
5D array [lon,lat,day,year,model] with GCM subset data.
RegLon
Vector of longitudes for the study area.
RegLat
Vector of latitudes for the study area.
XYcoords
Station coordinates (lon, lat) for downscaling data.
YearIni
Initial year of data (to compute leap years).
b
IDW exponent (2 as default).
Value
GCM time series for a point of interest.
作者：UCAS_Leon124
