There are two kinds of precipitation data on ERA5 datasets naming ‘total column rain water’ and ‘total precipitation’. I want to compare ERA5 precipitation data with observed data so which data sets will be better for this?
Use 'total precipitation'. ‘total column rain water’ means the precitable rain water stored within the atmoshperic column (that might fall as rain).
Hi,
Could I ask how obtain daily precipitation (00:00:00 to 00:00:00) from ERA5?
I know in ERA-Interim using time (00:00:00+12:00:00) with step 12, give daily precipitation. However how is about ERA5?
Sincerely
Ehsan
Hi Ehsan,
a main difference in ERA5 to ERA-Interim is that accumulated (or mean rate) fields are accumulated from the end of the previous time step or in other words: cover the last hour. That is, correct me if I'm wrong, you have to download all hourly fields of a day and sum them up afterwards by yourself (with e.g. CDO). I use this script for hourly total precipitation:
#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
server.retrieve({
"class": "ea",
"dataset": "era5",
"expver": "1",
"stream": "oper",
"type": "fc",
"levtype": "sfc",
"param": "228.128",
"date": "2016-01-01/to/2016-01-02",
"time": "00:06:00/18:00:00",
"step": "0/1/2/3/4/5/6/7/8/9/10/11",
"grid": "0.25/0.25",
"format": "netcdf",
"target": "test.nc"
})
'time' contains the two forecasts at 6UTC and 18UTC, and 'step' contains 1 to 11, because every step contains the sum over the last hour (and not from the start of the forecast as in ERA-Interim). For example, 6UTC + step 2 means the total precipitation from 7UTC to 8 UTC.
With that you cover:
6 UTC + step 1 +...+ step 11 --> 6 UTC to17 UTC and from
18 UTC + step 1 +...+ step 11 --> 18UTC to 5 UTC (next day).
Step 0 is import because it covers 5UTC to 6UTC and 17UTC to 18UTC.
Once you have downloaded the files you can do a 'cdo daysum ifile ofile' to get daily sums.
Dear Oliver
Thank you so much for your helpful comments.
I'll inform you if I conclude some thing else.
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