File:Chaco canyon pdsi 100-1700 ad 1.svg
![File:Chaco canyon pdsi 100-1700 ad 1.svg](https://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Chaco_canyon_pdsi_100-1700_ad_1.svg/800px-Chaco_canyon_pdsi_100-1700_ad_1.svg.png?20240112113839)
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Captions
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Summary
[edit]DescriptionChaco canyon pdsi 100-1700 ad 1.svg |
English: Chaco Canyon drought index PDSI 100 - 1700 AD |
Date | |
Source | Own work |
Author | Merikanto |
This image is based on LBDA.
Source of PDSI data
The 'Living Blended Drought Atlas (LBDA)' North American Drought Reconstruction for the last 2000 years
Cook, E.R., Seager, R., Heim, R.R., Vose, R.S., Herweijer, C., and Woodhouse, C. 2010. Megadroughts in North America: Placing IPCC projections of hydroclimatic change in a long-term paleoclimate context. Journal of Quaternary Science, 25(1), 48-61. doi: 10.1002/jqs.1303
NOAA Study Page:
https://www.ncei.noaa.gov/access/paleo-search/study/19119
R code to download and plot data
- 3
-
- north american drought atlas pdsi data extracting and viewing
- "R" code
-
library(raster)
library(terra)
library(ncdf4)
library(ggplot2)
library(pals)
download_data=0
yeara=100
yearb=1700
year1=901
- sitename="Mesa Verde"
- mesa verde
- sitee_lon =-108.488611
- sitee_lat =37.183889
- copan NOK
- sitename="Copán"
- sitee_lat = 14.838139
- sitee_lon = -89.142222
- chaco
- sitename="Chichén Itzá"
- sitee_lat=20.684167
- sitee_lon =-88.567778
- chaco
sitename="Chaco Canyon"
sitee_lat=36.058333
sitee_lon =-107.958889
- sitename="Mexico City"
- sitee_lat=19.433333
- sitee_lon=-99.133333
- los angeles
- sitename="Los Angeles"
- sitee_lon <- -118.25
- sitee_lat <- 34.05
- Cahokia
- sitee_lat=38.654722
- sitee_lon=-90.059444
- sitee_lon <- -80
- sitee_lat <- 40
iname1<-"nada_hd2_cl.nc"
url1<-"https://www.ncei.noaa.gov/pub/data/paleo/drought/LBDA2010/nada_hd2_cl.nc"
if(download_data==1)
{
download.file(url = url1,destfile = iname1)
}
- iname1<-"./northdata1/mex/NADAv2-2008.nc"
ncin1<- nc_open(iname1)
lon <- ncvar_get(ncin1, "lon")
lat <- ncvar_get(ncin1, "lat")
t <- ncvar_get(ncin1, "time")
pdsi0 <- ncvar_get(ncin1, "pdsi")
- print(t)
- stop(-1)
nc_close(ncin1)
- dim(pdsi0)
numu1=which(t==year1)
print(numu1)
print (dim(pdsi0))
- stop(-1)
pdsi1 <- pdsi0[numu1,,]
- image(pdsi1)
r1 <- raster(pdsi1, xmn=min(lon), xmx=max(lon), ymn=min(lat), ymx=max(lat), crs=CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs+ towgs84=0,0,0"))
print("s")
r1<-flip(r1)
print("s2")
s2<-raster(nrows=1024, ncols=1024)
crs(s2)<-crs(r1)
extent(s2)<-extent(r1)
- r2<-resample(r1, s2)
- writeRaster(r1 , filename="pdsi.nc", bandorder='BSQ',format="NetCDF", overwrite=TRUE)
- quit(-1)
- r1 <- flip(r1, direction='y')
plot(r1, col=rev(parula(64)))
ext1 <- extent(c(xmin = -96, xmax = -85,
ymin = 13, ymax = 22))
r2 <- crop(x = r1, y = ext1)
plot(r2, col=rev(parula(64)) )
- quit(-1)
print( dim(pdsi0))
- pdsix0=as.matrix(pdsi0)
- print( dim( t(pdsix0)))
- quit(-1)
pdsix0<- aperm(pdsi0, c(3,2,1))
print( dim(pdsix0))
r_brick <- brick(pdsix0, xmn=min(lat), xmx=max(lat), ymn=min(lon), ymx=max(lon), crs=CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs+ towgs84=0,0,0"))
str(r_brick)
- quit(-1)
- print( dim( t(pdsi0)))
r_brick <- flip(t(r_brick), direction='y')
pdsi_series <- extract(r_brick, SpatialPoints(cbind(sitee_lon,sitee_lat)), method='simple')
print(pdsi_series)
- quit(-1)
print("pazka")
selyears2=seq(from=yeara, to=yearb, by=1)
- selitems2<-2005-selyears2
selitems2=selyears2
pdsis2=t(pdsi_series[yeara:yearb])
- sitee_lat
- print(selyears2)
- print(selitems2)
- print(pdsis2)
x=selyears2
y=pdsis2
fit1 <- smooth.spline(x, y)
- valu2=values <- loess(y ~ x)
- y2=predict(valu2)
- dev.new(width = 1200, height = 600, unit = "px")
title1=paste0("Drought index PDSI at ", sitename)
pdf(file = paste0("out.pdf"), width = 16, height = 8, colormodel = "rgb")
plot(x, y, type="l", lwd=2, col="red", lty=1,
main=title1,
xlab="Year AD",
ylab="PDSI",
cex.lab=2, cex.axis=1.5, cex.main=2, cex.sub=1.5
,xaxt="n"
)
axis(1, at = seq(yeara, yearb, by = 50), cex.axis=1.5)
grid(nx = NULL, ny = NULL,
lty = 2,
col = "gray",
lwd = 1)
lines(x,y , col="#3f0000", lwd=5,add=T)
# lines(fit1, col = "blue", lwd = 2)
abline(h = 3, col="blue", lwd=2, lty=2)
abline(h = 0, col="green", lwd=2, lty=2)
abline(h = -3, col="red", lwd=2, lty=2)
- axis(1, xaxp=c(700, 1800, 19), las=2)
- lines(x,y,col = "red",lwd = 4, add=T)
dev.off()
system("pdf2svg out.pdf out.svg")
print(".")
quit("yes")
Licensing
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This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication. |
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http://creativecommons.org/publicdomain/zero/1.0/deed.enCC0Creative Commons Zero, Public Domain Dedicationfalsefalse |
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current | 11:38, 12 January 2024 | ![]() | 1,440 × 720 (121 KB) | Merikanto (talk | contribs) | Uploaded own work with UploadWizard |
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