Load the necessary packages:

library(ncdf4);
library(ncdf4.helpers);
library(maps);
library(RColorBrewer)
library(lattice)
library(latticeExtra)

Set working directory:

setwd("C:\\Users\\Ledi\\Documents\\FunR")
  1. read HadCRUT data: available from: # https://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/gridded_fields/HadCRUT.4.6.0.0.median_netcdf.zip
nc   <- nc_open(file.path(getwd(),"HadCRUT.4.6.0.0.median.nc")); # open netcdf file
tobs <- ncvar_get(nc,"temperature_anomaly"); # load temperature anomaly
ts   <- ncvar_get(nc,"time"); # load the time
lat  <- ncvar_get(nc,"latitude") # load the latitude
lon  <- ncvar_get(nc,"longitude") # load the longitude

Get the units:

tunits<-ncatt_get(nc,"time",attname="units")

tunits = “days since 1850-1-1 00:00:00”

tustr<-strsplit(tunits$value, " ")

Check the data:

date<-as.character(as.Date(ts,origin=unlist(tustr)[3]))

Flag missing data:

tobs[t<-90] = NA
tobs[t>490] = NA

Load global mean surface temperature data from giss temp: https://data.giss.nasa.gov/gistemp/

gmst = read.csv(file.path(getwd(),'global_temps_monthly.csv'),skip = 1,header=TRUE)

Annual avarage:

gmst <- data.frame(Year = gmst$Year, t = rowMeans(gmst[, 2:13], na.rm = T))

Visualisation of global mean temperature data:

plot(gmst,type="l",col="red",
main="GMST",xlab="Years",ylab="T Anomaly")

legend("topleft",
         legend=c("GIS TEMP"),
         col= c("red"), lty=1,lwd=1,bty="n")

  1. Create annually averaged gridded data from HadCRUT. 3a. visualize the data.

Pick out an index:

year_index <- which(date=="1901-06-16")
mapmat= tobs[,,year_index];
int=seq(-6,6,length.out = 11);
colors <- rev(brewer.pal(10, "RdYlBu"))
rgb.palette <- colorRampPalette(colors)
filled.contour(lon, lat, mapmat, color.palette=rgb.palette, levels=int,
                plot.title=title(main=paste0('HadCRUT Anom. in ', date[year_index]),
                xlab="Latitude",ylab="Longitude", cex.lab=1.5),
                plot.axes={axis(1, cex.axis=1.5);
                axis(2, cex.axis=1.5);
                map('world', add=TRUE);
                grid()},
                key.title=title(main="[oC]"),
                key.axes={axis(4, cex.axis=1.5)})

Repeat the same for a different date:

year_index2 <- which(date=="2017-08-16")
 
mapmat= tobs[,,year_index2];
int=seq(-6,6,length.out = 11)
 
colors <- rev(brewer.pal(10, "RdYlBu"))
rgb.palette <- colorRampPalette(colors)
filled.contour(lon, lat, mapmat, color.palette=rgb.palette, levels=int,
                plot.title=title(main=paste0('HadCRUT Anom. in ', date[year_index2]),
                                 xlab="Latitude",ylab="Longitude", cex.lab=1.5),
                plot.axes={axis(1, cex.axis=1.5);
                    axis(2, cex.axis=1.5);
                    map('world', add=TRUE);
                    grid()},
                key.title=title(main="[oC]"),
                key.axes={axis(4, cex.axis=1.5)})

Pre-allocate a blank array:

allyears <- format(as.Date(date, format="%Y-%m-%d"),"%Y")
years <- unique(allyears)
tann <- array(NA,c(dim(tobs)[1:2],length(years))) 
for (i in 1:length(years)){
  tann[,,i]<-apply(tobs[,,allyears==years[i]],c(1,2),mean,na.rm=TRUE)
}
  1. Creating a global mean surface temperature timeseries. 4a. Ignorant averaging.

    Dimensions of tann are long x lat x year.

    To get a zonal average want to average so that the output is lat x year.

    To get a meridional avarage, want output to be lon x year.

merid_means<-apply(tann,c(1,3),mean,na.rm=TRUE)
mean_merid_means <- apply(merid_means,2,mean,na.rm=TRUE)

Calculate the mean of the zonal means:

zonal_means<-apply(tann,c(2,3),mean,na.rm=TRUE)
mean_zonal_means <- apply(zonal_means,2,mean,na.rm=TRUE)

Plot the GIS GMST, the mean of the meridional means, and mean of zonal means on one plot:

plot(gmst,type="l",col="red",
     main="GMST",xlab="Years",ylab="T Anomaly")
lines(years, mean_merid_means, type="l", col="blue")
lines(years, mean_zonal_means, type="l", col="green")

legend("topleft",
               legend=c("GIS TEMP", "MERID MEAN", "ZONAL MEAN"),
               col= c("red", "blue", "green"), lty=1,lwd=1,bty="n")

Plot the zonal and meridional means as differences relative to the GIS temp:

Note: GIS runs from 1880 to 2017; hadcrut from 1850 to 2017
year1880<- which(years==1880)
year1850 <- which(years==1850)
year1880
## [1] 31
years[year1880:168]
##   [1] "1880" "1881" "1882" "1883" "1884" "1885" "1886" "1887" "1888" "1889"
##  [11] "1890" "1891" "1892" "1893" "1894" "1895" "1896" "1897" "1898" "1899"
##  [21] "1900" "1901" "1902" "1903" "1904" "1905" "1906" "1907" "1908" "1909"
##  [31] "1910" "1911" "1912" "1913" "1914" "1915" "1916" "1917" "1918" "1919"
##  [41] "1920" "1921" "1922" "1923" "1924" "1925" "1926" "1927" "1928" "1929"
##  [51] "1930" "1931" "1932" "1933" "1934" "1935" "1936" "1937" "1938" "1939"
##  [61] "1940" "1941" "1942" "1943" "1944" "1945" "1946" "1947" "1948" "1949"
##  [71] "1950" "1951" "1952" "1953" "1954" "1955" "1956" "1957" "1958" "1959"
##  [81] "1960" "1961" "1962" "1963" "1964" "1965" "1966" "1967" "1968" "1969"
##  [91] "1970" "1971" "1972" "1973" "1974" "1975" "1976" "1977" "1978" "1979"
## [101] "1980" "1981" "1982" "1983" "1984" "1985" "1986" "1987" "1988" "1989"
## [111] "1990" "1991" "1992" "1993" "1994" "1995" "1996" "1997" "1998" "1999"
## [121] "2000" "2001" "2002" "2003" "2004" "2005" "2006" "2007" "2008" "2009"
## [131] "2010" "2011" "2012" "2013" "2014" "2015" "2016" "2017"
merid_means[year1880:168]
##   [1]  0.015859008 -0.113658805  0.045033487 -0.191485671 -0.314136781
##   [6] -0.367997795 -0.843229599 -0.619653930 -0.762922705  0.053306513
##  [11] -0.432949510  0.061192007 -0.509140567 -0.281407002 -0.003170180
##  [16] -0.158106353 -0.359635223 -0.574381120 -0.226700453  0.247145196
##  [21] -0.094131382 -0.476865010 -0.292555586  0.165821457  0.014278571
##  [26] -0.152581270 -0.274938188 -0.202398700 -0.286091771 -0.492952027
##  [31] -0.310045857 -0.145487936  0.285891225 -0.148617491  0.094751841
##  [36]  0.315241910  0.041411316  0.154607928  0.638557178 -0.123477879
##  [41] -0.630748417 -1.133595619 -0.561039813 -0.733743883 -0.515140734
##  [46] -0.720536169 -0.345388525 -0.095280324 -0.057890887 -0.589819980
##  [51] -0.251933534  0.237454440 -0.259872660  0.323816282 -0.632795245
##  [56] -0.436226184 -0.150800257 -0.020030238  0.066819035 -0.047359703
##  [61] -0.449192484 -0.441801499 -0.197559208 -0.379473193 -0.222055690
##  [66] -0.542989723 -0.328647702 -0.230537231 -0.294841128  0.052173599
##  [71] -0.186742047 -0.185113704  0.132129410  0.188139430 -0.034646626
##  [76] -0.183710160 -0.378200167 -0.441020733 -0.842646120 -0.299258332
##  [81]  0.211268913  0.059353772  0.044771322  0.422436999  0.130065574
##  [86] -0.070905015  0.245927978 -0.008862256 -0.776718610 -0.477192240
##  [91] -0.332012746 -1.039243659 -0.252975312 -0.228197258 -0.326782186
##  [96]  0.086638802 -0.376009146 -0.560748763 -0.785938399 -0.651250665
## [101] -0.174491655 -0.330403016  0.053996742 -0.144795445 -0.139717361
## [106]  0.212022866 -0.052821385  0.149384317 -0.543264228 -0.183300039
## [111]  0.104401269 -0.314170341 -0.050764014 -0.935934230 -0.916268319
## [116] -0.223459736  0.066285172 -0.735457022 -1.267891344 -0.461576599
## [121] -0.360228888  0.049003725 -0.212539162 -0.347084387 -0.537711834
## [126] -0.368655648 -0.037284551 -0.137087448 -0.522239484 -0.527300150
## [131] -0.414555058 -0.502935970 -0.639767353 -0.580369833 -0.427173339
## [136] -0.603951462 -0.352515968 -0.658661335
zonal_means[1880:168]
##    [1] -0.3450987394 -0.2397433458 -0.3643823012 -0.3870130916
##    [5] -0.4364269972           NaN           NaN           NaN
##    [9]           NaN  0.4531621933 -1.5041078497 -1.3550889338
##   [13] -0.3946996428 -0.0618376049 -0.1593984983 -0.1862119135
##   [17] -0.1468234503 -0.1330437787 -0.0399527783 -0.1045517728
##   [21] -0.0528681887 -0.0986475648 -0.1136891609 -0.0018965370
##   [25] -0.1720916207 -0.1951834341 -0.2462200516 -0.1448659276
##   [29] -0.0561991006  0.0244453305  0.0374006388  0.0033218221
##   [33] -0.4644922283 -0.8449654363 -0.7406421077 -0.7997424393
##   [37] -0.0815431718  0.7035872720 -0.6980111599           NaN
##   [41]           NaN           NaN           NaN           NaN
##   [45]           NaN           NaN -2.2506944423 -1.2177743961
##   [49] -0.6969341557 -0.7025450562 -0.0643728686 -0.1784605085
##   [53] -0.1776581045 -0.0989979708 -0.0891785039  0.0264003703
##   [57]  0.0163944135 -0.0284150638  0.0471277312  0.1240995850
##   [61]  0.0969846834  0.1276664083  0.2419441866  0.2313003466
##   [65]  0.2781578859  0.2122223564  0.1138851874 -0.1121101032
##   [69] -0.4381965251 -0.7666010660 -0.9740333764 -0.5195326961
##   [73] -0.1282002897  0.3758033568  1.0511298875           NaN
##   [77]           NaN           NaN           NaN           NaN
##   [81]           NaN           NaN -1.5600533823 -1.4633981360
##   [85] -1.3983986480 -0.8913164122  0.1606486156 -0.1050225726
##   [89] -0.1561054402 -0.0411832328 -0.0660582125 -0.2939882369
##   [93] -0.2948287607 -0.3174775142 -0.2615056190 -0.1391248157
##   [97] -0.1321322235 -0.1406843403  0.1727478460  0.1177536468
##  [101]  0.0235612830 -0.0767222478 -0.0443634266 -0.1200323979
##  [105] -0.2586492958 -0.4523078639 -0.8268439487 -0.5882128439
##  [109]  0.0224512842  0.2719163299  1.1769194330           NaN
##  [113]           NaN           NaN           NaN           NaN
##  [117]           NaN -0.8869974017 -1.1004469846 -0.9798086013
##  [121] -0.6038238552 -0.5142080091  0.0459693820 -0.3108261319
##  [125] -0.4188970080 -0.4344428126 -0.2127945809 -0.1792778917
##  [129] -0.2473947463 -0.2568229916 -0.0069405513 -0.2271905369
##  [133] -0.3613075633 -0.4764405476 -0.4473258996 -0.3841872363
##  [137] -0.4081358876 -0.2390914706 -0.2978207709 -0.3433116887
##  [141] -0.4632992324 -0.5677243175 -0.9495466985 -0.7186509774
##  [145] -0.1737041215  0.1302515445 -0.3960517168           NaN
##  [149]           NaN           NaN           NaN           NaN
##  [153]           NaN           NaN -1.0519103805 -0.3485651175
##  [157] -0.1988899624 -0.3353283578 -0.3568444877 -0.4247810299
##  [161] -0.4207019909 -0.4055943539 -0.2974920945 -0.2167480751
##  [165]  0.0784036720 -0.0820811668  0.0685196968 -0.0093908324
##  [169]  0.1620789964  0.0529856809  0.1416499325  0.3244238707
##  [173]  0.2282851102  0.1967117385 -0.1766516107 -0.3281713925
##  [177] -0.4193113477 -0.5255938347 -0.6692455626 -0.6091071206
##  [181] -0.0942169168  0.2019819463  0.2001145418           NaN
##  [185]           NaN           NaN           NaN           NaN
##  [189]           NaN           NaN -1.0946034555 -1.0187404775
##  [193] -0.3212322309 -0.1311135980 -0.2792253316 -0.5094819429
##  [197] -0.4427831228 -0.3743500901 -0.1907655067  0.0022497235
##  [201]  0.0575340046 -0.1722796775 -0.0464247593  0.0035729918
##  [205]  0.1374869611  0.1078490770  0.1305174508  0.1804876074
##  [209]  0.1363747753  0.1490905465 -0.1301480266 -0.2343369104
##  [213] -0.4335272003 -0.3181887500 -0.5800274663 -0.1304330825
##  [217] -0.0062248021  0.2932533945  0.7261001840           NaN
##  [221]           NaN           NaN           NaN           NaN
##  [225]           NaN           NaN -1.7503660321 -1.6991895366
##  [229] -0.5503117667 -0.4140948019 -0.3067766304 -0.7004305040
##  [233] -0.3673609174 -0.4475593681 -0.1920905834 -0.3204395489
##  [237] -0.2627084750 -0.3129474858 -0.2255527990 -0.0624660205
##  [241] -0.1942786908 -0.1893792502 -0.1114643884 -0.1643680687
##  [245] -0.0475994821  0.0326406939 -0.2311029629 -0.2646298356
##  [249] -0.4686173609 -0.5935889328 -0.7948774865 -0.2948253697
##  [253] -0.2193340532  0.6244746560  0.4656965137           NaN
##  [257]           NaN           NaN           NaN           NaN
##  [261]           NaN           NaN -1.8250002563 -1.4288020457
##  [265] -0.6432648724 -0.3533871040 -0.1963918394 -0.3457629218
##  [269] -0.4051123270  0.0752738229  0.2195533256 -0.1451833116
##  [273] -0.4144760180 -0.6443097032 -0.6498882056 -0.5644724850
##  [277] -0.6789606719 -0.6699521928 -0.3983514459 -0.3370416394
##  [281] -0.2262674701 -0.1923579949 -0.2763271296 -0.2516870363
##  [285] -0.2760760489 -0.3240572863 -0.5193271730 -0.4199206864
##  [289] -0.3874932832 -0.7799425817  0.7859599590           NaN
##  [293]           NaN           NaN           NaN           NaN
##  [297]           NaN           NaN           NaN  0.0092902948
##  [301] -1.5824784987 -0.9686941563 -0.2104638076 -0.5330126876
##  [305] -0.8705396534 -0.4044255523 -0.0456074147 -0.3246909845
##  [309] -0.5504852296 -0.5767052398 -0.5172823186 -0.4749943767
##  [313] -0.5844405094 -0.7415842221 -0.5907570051 -0.5243546144
##  [317] -0.4921120652 -0.2868327622 -0.2476129389 -0.0375544841
##  [321] -0.1429231350 -0.1882797523 -0.4074299837 -0.1534208957
##  [325] -0.5831368109 -0.0552618753  0.6661433354           NaN
##  [329]           NaN           NaN           NaN           NaN
##  [333]           NaN           NaN           NaN -2.4678125138
##  [337] -1.8727179299 -0.9858090763 -0.5453181493 -0.7188594959
##  [341] -0.6299959915 -0.0884750182  0.1080779477 -0.1668060572
##  [345] -0.2321672613 -0.4076795030 -0.4118029138 -0.4745204415
##  [349] -0.5307908636 -0.4919098343 -0.6621844340 -0.5386396480
##  [353] -0.2146041505 -0.2264021576 -0.1596518854  0.0158755229
##  [357] -0.2602119753 -0.2366411485 -0.4190268523 -0.4223078738
##  [361] -0.2720875429 -0.5776741311  0.8827559352           NaN
##  [365]           NaN           NaN           NaN           NaN
##  [369]           NaN           NaN -1.2937251367 -1.8127022523
##  [373] -0.8961516213 -0.5995856587 -0.3232186228 -0.4229105829
##  [377] -0.4186038203 -0.3254102522 -0.1748345051 -0.1924196764
##  [381] -0.2630194671 -0.1597928952  0.1113646490 -0.0554196147
##  [385] -0.0508559628 -0.0625782344 -0.1166682280 -0.1042373784
##  [389] -0.3311499125 -0.3537512147 -0.2817919653 -0.4112455203
##  [393] -0.4892486964 -0.2187382202 -0.4530699879 -0.4333597526
##  [397] -0.3640837594  0.0283473230  0.8346993153           NaN
##  [401]           NaN           NaN           NaN           NaN
##  [405]           NaN  0.7401356444 -1.0223534598 -1.1313616838
##  [409] -0.4080130210 -0.1116985382 -0.2196646803 -0.4897477907
##  [413] -0.2522042613 -0.1836257030 -0.0304894572 -0.1581483172
##  [417] -0.2854204311 -0.4118118159 -0.2416195586 -0.2837381459
##  [421] -0.5116952239 -0.7421333292 -0.5891230313 -0.3484216008
##  [425] -0.4730627937 -0.4993618411 -0.4824018284 -0.3583365957
##  [429] -0.3838673138 -0.1849240134 -0.3743584751 -0.5924588003
##  [433] -0.2924123439 -0.4893655593  1.3759305477           NaN
##  [437]           NaN           NaN           NaN           NaN
##  [441]           NaN           NaN -1.2437441831 -1.4263903868
##  [445] -0.3749158248  0.0963054237 -0.1080863378 -0.4161240535
##  [449] -0.1195897249  0.0594084916 -0.3554055476 -0.1731941970
##  [453] -0.1780669866 -0.1126468557  0.0403522664  0.0508895808
##  [457]  0.1512947948 -0.0224347804  0.1369029633  0.1810921966
##  [461]  0.0047131502  0.0548579635 -0.1930182470 -0.1282789035
##  [465] -0.4449915466 -0.3759184215 -0.4440258256 -0.2997417011
##  [469] -0.1076526758  0.1900978392  0.1887520154           NaN
##  [473]           NaN           NaN           NaN           NaN
##  [477]           NaN -0.4277266264 -1.5648320967 -2.0226612657
##  [481] -1.7649960840 -1.6923782525 -0.4807907754 -0.1570356495
##  [485] -0.5005422719 -0.3598928848 -0.2029544107 -0.2830260064
##  [489] -0.2179282909  0.0401544413  0.0326430233 -0.0079427155
##  [493]  0.0899670880  0.2297871363  0.1997486384  0.0531376253
##  [497] -0.0462911915  0.0055215289 -0.1409287148 -0.3503494534
##  [501] -0.5619924887 -0.6366246917 -0.7680699230 -0.6548943291
##  [505] -0.4224207163  0.1662816400           NaN           NaN
##  [509]           NaN           NaN           NaN           NaN
##  [513]           NaN           NaN           NaN -0.1194217635
##  [517] -0.3513118849 -0.3841337354 -0.1114288757 -0.4418965031
##  [521] -0.4885993044 -0.4431497678 -0.1646522639 -0.2046810564
##  [525] -0.3756478508 -0.3032667400 -0.2541602508 -0.3225472130
##  [529] -0.3885887270 -0.4887249063 -0.3301739390 -0.3544438155
##  [533] -0.3337358170 -0.3586448485 -0.4423569324 -0.5108477369
##  [537] -0.4494896997 -0.3497752959 -0.5425062874 -0.5645945753
##  [541] -0.1592029219 -0.1109989860  0.4277849197           NaN
##  [545]           NaN           NaN           NaN           NaN
##  [549]           NaN           NaN -1.3645284263 -1.5358864446
##  [553] -1.6422632025 -1.0484811027 -0.4899490024 -0.1998765767
##  [557] -0.2210511501 -0.1206170659 -0.2483796447 -0.3072884489
##  [561] -0.6375473172 -0.4816010019 -0.2122127835 -0.2598826932
##  [565] -0.2654767872 -0.4674072897 -0.5299415083 -0.2548961482
##  [569] -0.1678147057 -0.2679343065 -0.2769033728 -0.2189135935
##  [573] -0.4065206176 -0.4548558459 -0.6025924272 -0.7126548825
##  [577] -0.4073493204 -0.1078252614  1.2624830008           NaN
##  [581]           NaN           NaN           NaN           NaN
##  [585]           NaN           NaN -0.3110533655 -0.5361559443
##  [589] -1.0121954624 -1.1302420142 -0.6322623493 -0.6807010387
##  [593] -0.5757060465 -0.3836820982 -0.3671519246 -0.5268065994
##  [597] -0.5483791022 -0.2212528167 -0.2220077630 -0.2448954837
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##  [621]           NaN           NaN -1.2812213441 -0.9836283578
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##  [653]           NaN           NaN           NaN           NaN
##  [657]           NaN           NaN -4.8986997604 -1.0760575706
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##  [693]           NaN           NaN           NaN -1.7283845040
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##  [729]           NaN           NaN -3.0404052019 -2.9474355185
##  [733] -1.2221528071 -1.0086062132 -0.5070509254 -0.6042445335
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##  [761]           NaN           NaN           NaN           NaN
##  [765]           NaN           NaN -1.5237787142 -0.5332627391
##  [769] -0.4461545337 -0.0954890763  0.0311445715 -0.2219021708
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##  [797]           NaN           NaN           NaN           NaN
##  [801]           NaN           NaN -0.8791440502 -0.9372991646
##  [805] -0.9521046717 -0.5277023391 -0.4602091370 -0.6872119704
##  [809] -0.7359427841 -0.0952266816 -0.0348320634  0.1541943328
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##  [829]  0.3876700896  1.0882632192           NaN           NaN
##  [833]           NaN           NaN           NaN           NaN
##  [837]           NaN  1.5683877468  0.3035521772  0.5733325695
##  [841]  0.1824652610  0.1960611428  0.3677433991  0.4916768531
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##  [865]  0.0125446095  0.9297015936  1.8666543365           NaN
##  [869]           NaN           NaN           NaN           NaN
##  [873]           NaN -0.0912745148 -0.1079256364 -1.2797551883
##  [877] -0.5867779905 -0.6476007128 -0.1937604438 -0.0246244315
##  [881]  0.2609462545  0.1096372873  0.1663237158  0.2419387845
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##  [901]  0.2316072304  0.3807586696  2.2470707893           NaN
##  [905]           NaN           NaN           NaN           NaN
##  [909]           NaN  0.5505373964  0.2473184019 -0.9370831406
##  [913] -0.5476379607 -0.4703285875 -0.5062665140 -0.3294951047
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##  [937]  0.1479468724  0.3140991356           NaN           NaN
##  [941]           NaN           NaN           NaN           NaN
##  [945]           NaN  0.8793428540 -0.9872630412 -1.1888831475
##  [949] -1.0380959026 -0.9200360551 -0.4285371641 -0.5856881826
##  [953] -0.8296885390 -0.3736083677 -0.0544382045 -0.2518610627
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##  [973]  0.1410508596  0.1975216656  2.4743952751           NaN
##  [977]           NaN           NaN           NaN           NaN
##  [981]           NaN  0.0484191328 -1.0187584116 -0.7914351721
##  [985] -0.7569139696 -0.4716285912  0.1870928871  0.2400450759
##  [989] -0.4125502627 -0.0896180152  0.0294341714 -0.0976055534
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## [1013]           NaN           NaN           NaN           NaN
## [1017]           NaN           NaN -1.2033895507 -0.7013362419
## [1021] -0.7748901972 -0.1940283276 -0.0411956774  0.1189543560
## [1025] -0.2991547161 -0.1218965280 -0.0600430826 -0.0418613736
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## [1045] -0.5704658912 -0.1854864767 -0.2757589817           NaN
## [1049]           NaN           NaN           NaN           NaN
## [1053]           NaN           NaN -1.4938158592 -0.3446311195
## [1057] -0.3734266646  0.6854862599  0.4339882804  0.2884519079
## [1061] -0.1946640035 -0.2836950282 -0.2716940167 -0.3982876511
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## [1081] -0.3016493131 -0.1155968921           NaN           NaN
## [1085]           NaN           NaN           NaN           NaN
## [1089]           NaN  0.0495396523 -0.9031655692 -1.4435809853
## [1093] -1.5101115001 -1.2315751077 -0.3766696409 -0.7975936049
## [1097] -0.6842539429 -0.2419434929  0.0599893776 -0.0523571508
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## [1117] -0.1343136983 -0.2555113924  0.1495307088           NaN
## [1121]           NaN           NaN           NaN           NaN
## [1125]           NaN           NaN -1.3106479213 -0.5062396006
## [1129]  0.0906587372 -0.8049006577 -0.4371861036 -0.5610795329
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## [1153] -0.2223089352 -0.3461803889 -1.1462328434           NaN
## [1157]           NaN           NaN           NaN           NaN
## [1161]           NaN           NaN           NaN -0.9068776307
## [1165] -0.8605639652 -0.3597302683  0.4499968316  0.2608529960
## [1169] -0.4326759160 -0.7794279806 -0.2873758228 -0.1898428059
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## [1189] -0.0197145464  0.0583910015  0.9665241838           NaN
## [1193]           NaN           NaN           NaN           NaN
## [1197]           NaN           NaN           NaN -0.5270235725
## [1201] -0.8785836813 -0.1855022620  0.2376685366  0.3903454304
## [1205]  0.2095216865 -0.0249156440 -0.2111031271 -0.2450159282
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## [1225]  0.7663096387  0.1902116229           NaN           NaN
## [1229]           NaN           NaN           NaN           NaN
## [1233]           NaN           NaN           NaN -1.9934543362
## [1237] -1.9935234468 -1.5447235930 -0.5687460130 -0.2757992618
## [1241] -0.1083763273 -0.4197740752 -0.0460982462 -0.3799296483
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## [1261] -0.4634054754 -0.6437671557           NaN           NaN
## [1265]           NaN           NaN           NaN           NaN
## [1269]           NaN           NaN           NaN -1.1340300068
## [1273] -1.9607718540 -0.5169585925  0.1019720085  0.4402361230
## [1277]  0.1604244674 -0.0720584833  0.1309855880 -0.4570451499
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## [1293] -0.2452525425 -0.5145726802 -0.5827391657 -0.2295049246
## [1297]           NaN           NaN           NaN           NaN
## [1301]           NaN           NaN           NaN           NaN
## [1305]           NaN           NaN           NaN -1.4376702656
## [1309] -0.8000635517 -0.4818490104 -0.6268698782 -0.3435398084
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## [1333] -0.5438044548 -0.5689172536           NaN           NaN
## [1337]           NaN           NaN           NaN           NaN
## [1341]           NaN           NaN           NaN -0.7371397863
## [1345] -1.1408404783 -0.9132695217 -0.8076443192 -0.8347901422
## [1349] -0.3840955609 -0.2592406915 -0.3686761714 -0.2444301129
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## [1373]           NaN           NaN           NaN           NaN
## [1377]           NaN           NaN           NaN  0.9132103721
## [1381] -0.1362477155 -0.0100759374  0.3921173241  0.6873830197
## [1385]  0.0185401855 -0.1697857158 -0.2459992355 -0.1907355504
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## [1405]           NaN           NaN           NaN           NaN
## [1409]           NaN           NaN           NaN           NaN
## [1413]           NaN           NaN           NaN -1.0717503981
## [1417] -1.6819962926 -1.9976240716 -1.3158666904 -0.9162262628
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## [1445]           NaN           NaN           NaN           NaN
## [1449]           NaN           NaN           NaN  0.7178581543
## [1453] -0.7769600833 -0.4120222054 -0.4199325252 -0.6401769672
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## [1481]           NaN           NaN           NaN           NaN
## [1485]           NaN           NaN           NaN -0.1870262194
## [1489] -1.1598312362 -1.1013100719 -0.9326246764 -0.7836004906
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## [1517]           NaN           NaN           NaN           NaN
## [1521]           NaN           NaN           NaN -0.6788679906
## [1525] -1.9004844227  0.3646014074 -0.0004649660  0.1710577708
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## [1549] -0.2738287302  0.0412561852  0.2193313241           NaN
## [1553]           NaN           NaN           NaN           NaN
## [1557]           NaN           NaN           NaN  0.9077309452
## [1561] -0.6479053686  0.2513050548 -0.1905457203 -0.2685489621
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## [1585] -0.4706459532  0.0831120034  0.8113767803           NaN
## [1589]           NaN           NaN           NaN           NaN
## [1593]           NaN           NaN           NaN -0.5967547523
## [1597] -0.7500189813  0.8751648066  0.3051024546 -0.0820065062
## [1601] -0.4395513235 -0.7181642943 -0.7982366828 -0.2046917889
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## [1621] -0.5815191361 -0.1704192025           NaN           NaN
## [1625]           NaN           NaN           NaN           NaN
## [1629]           NaN           NaN           NaN -1.7943608395
## [1633] -0.2068463523 -0.8154581295 -0.9348559743 -0.3072229879
## [1637] -0.3894724690 -0.2481600554 -0.5177331815 -0.3427091889
## [1641] -0.0228474632 -0.2562944429 -0.3775874608 -0.4075338578
## [1645] -0.4683332520 -0.4755219238 -0.4059716759 -0.4491287146
## [1649] -0.3782515813 -0.5842528715 -0.5346400193 -0.2306816061
## [1653] -0.1759489949 -0.2167002668 -0.4232970371 -0.5302560396
## [1657] -0.2950827035 -0.1283268350 -0.4217897654           NaN
## [1661]           NaN           NaN           NaN           NaN
## [1665]           NaN           NaN -1.4058441222 -0.7597541934
## [1669] -1.2373706003 -0.5617681324 -1.1073867635 -0.7599229003
## [1673]  0.0390487652  0.3148417535  0.0569200498 -0.1881181503
## [1677] -0.0993041968 -0.3442139703 -0.1682184970 -0.1060696199
## [1681] -0.1454859801 -0.0336193624 -0.1152324052 -0.1502742015
## [1685] -0.2486367319 -0.4096227797 -0.2238402571 -0.3477128928
## [1689] -0.4082937208 -0.2131613229 -0.4308149433 -0.5868189208
## [1693] -0.2280274528  0.0438421087           NaN           NaN
## [1697]           NaN           NaN           NaN           NaN
## [1701]           NaN           NaN           NaN  0.1499978781
## [1705] -0.9964171643 -0.2479996480 -0.0336040158  0.1874621472
## [1709] -0.1658006927 -0.0235374650  0.2353032304  0.1639615707
## [1713] -0.0886189539
merid_anom <- gmst$t - mean_merid_means[year1880:168]
zonal_anom <- gmst$t - mean_zonal_means[year1880:168]


plot(years[31:168],merid_anom,type="l",col="blue",
     main="GMST",xlab="Years", ylab="T Anomaly", ylim= c(-.2,.4))

lines(years[31:168], zonal_anom, type="l", col="green")

legend("topleft",
              legend=c("Mean of the Meridional Means Anomally", "Mean of Zonal Means Anomally"),
              col= c("blue", "green"), lty=1,lwd=1,bty="n")