【发布时间】：2018-09-19 11:47:35
【问题描述】：
所以我一直致力于从 NOAA 的 GHCN 气象站网络获取气候数据（特别是温度、降水）。我已经设法获得了与我所在地区相关的站点列表（约 200 个），并建立了一个循环，以便在指定的最小和最大日期之间的每一天为该列表中的每个站点获取特定的气候变量。最终我需要大约 10 年的数据。然而，我的简单循环需要永远获取这些数据，我想知道是否有更好的方法来优化它？此外，我真的想访问每月数据而不是每天，但 rnoaa 似乎没有 GHCN 每月数据的选项，因为唯一可用的函数是 ghcnd_search()。如果有人也知道如何挖掘每月而不是每日数据，那将不胜感激
车站列表：
df<-c("US1FLAL0048", "US1FLBK0003", "US1FLBV0002", "US1FLBV0006",
"US1FLBV0023", "US1FLBV0040", "US1FLBW0099", "US1FLCT0012", "US1FLDV0051",
"US1FLFR0006", "US1FLHL0003", "US1FLHN0009", "US1FLLB0001", "US1FLLE0005",
"US1FLLK0012", "US1FLLN0004", "US1FLLN0018", "US1FLMN0013", "US1FLMR0012",
"US1FLMR0033", "US1FLOK0017", "US1FLOR0028", "US1FLPS0002", "US1FLPS0018",
"US1FLPT0007", "US1FLSJ0012", "US1FLSM0008", "US1FLSS0044", "US1FLST0014",
"US1FLSW0008", "US1FLVL0035", "US1FLWK0001", "USC00080228", "USC00080236",
"USC00080369", "USC00080414", "USC00080478", "USC00080598", "USC00080737",
"USC00080945", "USC00080992", "USC00081163", "USC00081276", "USC00081306",
"USC00081544", "USC00081641", "USC00081651", "USC00081978", "USC00082008",
"USC00082046", "USC00082150", "USC00082229", "USC00082288", "USC00082298",
"USC00082391", "USC00082418", "USC00082441", "USC00082850", "USC00082915",
"USC00082944", "USC00083020", "USC00083153", "USC00083163", "USC00083168",
"USC00083207", "USC00083209", "USC00083470", "USC00083874", "USC00083909",
"USC00083956", "USC00083986", "USC00084050", "USC00084095", "USC00084210",
"USC00084289", "USC00084320", "USC00084366", "USC00084394", "USC00084412",
"USC00084461", "USC00084625", "USC00084662", "USC00084731", "USC00084802",
"USC00085076", "USC00085099", "USC00085184", "USC00085275", "USC00085359",
"USC00085377", "USC00085539", "USC00085612", "USC00085667", "USC00085879",
"USC00085895", "USC00085973", "USC00086065", "USC00086078", "USC00086129",
"USC00086240", "USC00086315", "USC00086406", "USC00086414", "USC00086618",
"USC00086657", "USC00086764", "USC00086767", "USC00086828", "USC00086842",
"USC00086999", "USC00087020", "USC00087025", "USC00087205", "USC00087228",
"USC00087261", "USC00087304", "USC00087397", "USC00087429", "USC00087760",
"USC00087826", "USC00087851", "USC00087869", "USC00087886", "USC00087982",
"USC00088368", "USC00088529", "USC00088620", "USC00088756", "USC00088782",
"USC00088824", "USC00088942", "USC00089120", "USC00089176", "USC00089219",
"USC00089401", "USC00089430", "USC00089566", "USC00089640", "USC00089795",
"USR0000FBLO", "USR0000FCAC", "USR0000FCEN", "USR0000FCHE", "USR0000FLSU",
"USR0000FMER", "USR0000FMIL", "USR0000FNAV", "USR0000FOAS", "USR0000FOCH",
"USR0000FOLU", "USR0000FRAC", "USR0000FSAN", "USR0000FSTM", "USR0000FSUM",
"USR0000FWIL", "USW00003818", "USW00003853", "USW00012812", "USW00012815",
"USW00012816", "USW00012818", "USW00012819", "USW00012832", "USW00012833",
"USW00012834", "USW00012835", "USW00012836", "USW00012838", "USW00012839",
"USW00012841", "USW00012842", "USW00012843", "USW00012844", "USW00012849",
"USW00012850", "USW00012854", "USW00012871", "USW00012873", "USW00012876",
"USW00012882", "USW00012885", "USW00012888", "USW00012894", "USW00012895",
"USW00012896", "USW00012897", "USW00013884", "USW00013889", "USW00013899",
"USW00053847", "USW00053853", "USW00053860", "USW00092805", "USW00092806",
"USW00092809", "USW00092811", "USW00092821", "USW00093805", "USW00093837",
"USW00093841")
代码：
library(rnoaa)
options(noaakey = "your api key")
data<-matrix(, nrow=0, ncol=0) #create empty matrix
for (i in 1:length(df)){
a<-ghcnd_search(stationid=df[1],var='TMAX',date_min='2010-1-30',date_max='2015-12-31')
data=rbind(data,a$tmax)
}
【问题讨论】：
-
难以优化，但在循环的每次迭代中增加
data矩阵的成本很高。由于您知道您的日期范围，并且数据是每天的，以及将查询多少个站点，您可以预先分配一个适当大小的矩阵并随时填写矩阵的块。就目前而言，您正在一遍又一遍地破坏和创建数据框。 -
您确定使用
rnoaa可以获得10 年的数据吗？ IIRC 他们有 1000 天的最大限制