Questions tagged [reanalysis]

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14
votes
1answer
264 views

Odd structures in 66 year NCEP daily temperature reanalysis

I have done some simple analyses of historical surface temperature from the NOAA NCAR/NCEP reanalysis (downloaded from ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.dailyavgs/surface/air.sig995.*.nc)...
10
votes
0answers
90 views

How are scatterometer observations standardised before being fed into reanalysis models?

This very basic question occurred to me during a talk on reanalysis data sets. Often we know the observations produced by a particular instrument, say rain radar, are biased from one year to the next ...
7
votes
2answers
4k views

Extracting Regional Data from ERA5

This is coming from a newcomer, so please be kind. As I delve into the world of meteo data and reanalysis for the first time, I found that acquiring weather data is a lengthy process, so I'm shouting ...
6
votes
2answers
749 views

What is the meaning of step in ERA reanalysis data?

The webpage to download ERA data includes an option called "time" which is intuitive, but also an option called "step". I can't find an explanation of the meaning of this. It can't be a time step ...
6
votes
2answers
100 views

ERA Interim problem with Waves

Has anyone had a problem with significant wave height (swh) and mean wave period (mwp) from ERA-Interim not matching very well with either a time series of measurements or a different model? Or does ...
5
votes
1answer
692 views

What is the height above ground of NCEP/NCAR Reanalysis 1 variables?

I am confused regarding the height above ground of this data set. http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html I have to reprocess this data set and need to know this piece of ...
5
votes
0answers
80 views

NCEP reanalysis latitude and longitude represent center of cell?

I can't find any information regarding the lat and long in the NCEP Reanalysis. Do they represent the center of the cell?
4
votes
1answer
90 views

Why is ferret giving me error that the region is not 2D while plotting

I have downloaded ERA5 data and am trying to plot temperature variable. The problem I am facing is that even after providing a 2D area for plotting, ferret is giving an error saying that the region ...
4
votes
1answer
229 views

Single-layer water content variables

In different reanalysis products (ERA 20C and NOAA/OAR/ESRL/PSD 20th Century daily data specifically) one can find the following variables: Total column water (ERA) Total column rain water (ERA) ...
4
votes
2answers
203 views

How to calculate 'real-world' geometric height from ERA reanalysis data

This seems like a really simple question, but I have been struggling for a couple of days to find an answer online or in the ERA documentation. I am using ERA5 and ERA Interim reanalyses to get ...
4
votes
0answers
274 views

Extracting point data from ERA5 CDS API

I have been extracting ERA5 data through the Web API. Now I am shifting to CDS API. In the web API I used the below code to download time series data at a particular lat/lon. In the CDS API, I can't ...
3
votes
1answer
4k views

ERA Interim, how to handle total precipitation

I am trying to compute accumulated annual precipitation for year 2000-2001 based on the ERA Interim, but I am stuck with some unresolved questions: If I download the synoptic monthly means of "total ...
3
votes
1answer
680 views

How to calculate 3-hour flux values in ERA-Interim?

Referring to the post: https://www.myroms.org/forum/viewtopic.php?f=30&t=3003 I understood how to calculate the slhf and sshf for 03, 06, 09 and 12 time steps. But I have values for 00, 15, 18 ...
3
votes
2answers
54 views

How can I account for rainfall effects on air pollution?

How can I adjust black carbon surface mass air pollution concentrations (ug/m3) for rainfall effects? Specifically, I have monthly and daily averaged black carbon pollution data (i.e. 2.0ug/m3 Jan ...
3
votes
1answer
1k views

shortwave and longwave radiation terminology, direct, beam, PAR, flux?

Some reanalysis data sets provide different components of shortwave radiation (near infrared and visible) and longwave. They are referred as radiation or flux. Also there is no mention of "direct" ...
3
votes
1answer
223 views

CFSR hourly surface wind time series

I am looking for hourly surface wind reanalysis data for the past two years. I am looking at the CFSR/CFSv2 data accessible from UCAR: http://rda.ucar.edu/datasets/ds094.1 The 6-hourly products are "...
2
votes
1answer
286 views

Why is radiation and total precipitation not available in ERA Interim Reanalysis at step 0?

ERA Interim reanalysis http://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc surface level variables such as radiation and precipitation, but also many others, are only available at time ...
2
votes
1answer
913 views

Does Climate Data Store provide daily mean of ERA 5 reanalysis data?

I have been meaning to download the daily mean of ERA 5 reanalysis data from the Copernicus Climate Data Store, but couldn't find it. I need the data on pressure levels and currently I am ...
2
votes
1answer
70 views

How reanalysis data influence our research/results?

I am a student and I have a very simple and yet important question about reanalysis data. Recently, I attended a workshop where various other students discussing the use of ERA5 reanalysis data on ...
2
votes
1answer
3k views

Error trying to download ERA5 data: Exception: Missing/incomplete configuration file: C:\Users\username/.cdsapirc

I am new with Python so please be kind. I want to download data from ERA5 and so far I have installed the CDS API package and followed all the instructions from https://cds.climate.copernicus.eu/api-...
2
votes
2answers
731 views

What's the difference between snow cover and fractional snow cover?

What's the difference between snow cover and fractional snow cover? Are they kind of synonyms? What would be a definition of fractional snow cover? thanks a lot!
2
votes
0answers
28 views

Where I can download Vertical Velocity data in the MERRA Reanalysis

I want to download Vertical Velocity data in the MERRA Reanalysis. But I can not find it even I carefully went through the entire list of MERRA data. This is the website I searched through: enter link ...
2
votes
0answers
48 views

ERA-5 data downloader… other than CDS-API?

The CDS API does not behave well on our machines. Has anyone had any luck scripting their own ERA-5 reanalysis large-data download script? Perhaps something that is not nearly as large, clunky, and ...
2
votes
0answers
64 views

Quantifying long term melt record on glacier surface

I intend to create a long term melt record on a glacier surface. What are parameters required to efficiently calculate the same using satellite, weather station observations & reanalysis datasets (...
1
vote
1answer
79 views

In meteorology, are satellite data “better” than reanalysis data?

More specifically, can it be argued that satellite data are more reliable because they are direct measurements of physical quantities, while reanalysis data depend on the processing and merging of ...
1
vote
2answers
217 views

ERA-Interim how to select only grid-points over land area?

I am using ERA-Interim data, e.g. total precipitation, and I want to take only observations over land areas. How can I filter the ERA-Interim dataset of precipitation to get only observations in grid-...
1
vote
1answer
43 views

Temperature at 2 m MERRA2

I need MERRA2 data with Temperature at 2m. I'm checking on https://disc.gsfc.nasa.gov/daac-bin/FTPSubset2.pl but I can't find this variable. Suggestions where I can find them? Or anyone that did ...
1
vote
1answer
67 views

MERRA-2 Reanalysis data V and U wind are missing values over land at 1000 hPa pressure level

I need 6-hour MERRA-2 reanalysis data to do some research. I downloaded the data from this website: https://disc.gsfc.nasa.gov/datasets/M2I6NPANA_5.12.4/summary?keywords=merra When I used ncview to ...
1
vote
1answer
76 views

How reliable is sea-ice concentration (fraction) data in ERA-Interim?

I am using sea-ice data from the European Reanalysis from ECMWF (ERA Interim), but some grid cells over land have sea-ice information. Not a big issue so far, because spatial discretization must ...
1
vote
0answers
31 views

How to specify a certain place in a (CDS) weather data query?

I am trying to get time series data for a specific place (latitude and longitude) for different weather elements from the CDS datapool. Therefore, I am using the cdsapi package and can run queries ...
1
vote
0answers
25 views

How to infer local precipitation from reanalysis data?

Let's say I'm extracting precipitation from a single pixel or region from a reanalysis (MERRA-2, ERA-5, Interim) dataset. I can infer a distribution for the daily data (Gamma, Pearson-III, e.g. link),...
1
vote
0answers
107 views

How can I convert a CERA-20C total precipitation dataset of "monthly means of daily means' (edmo) to mm/month?

I downloaded an edmo dataset of 1 ensemble of the cera-20c model. I want to convert these data, which are in [m], to mm/month. Further specifications: 0.125/0.125 grid, -29/30/-30/31 area. Example of ...
1
vote
0answers
58 views

How to calculate water vapor budget for a selected region in GRADS or MAT Lab

I need to calculate water vapor budget for a selected region. Can anyone suggest a specific link or code for the above mentioned tools please. I have seen a link for NCL but i am not familiar with ...
0
votes
1answer
59 views

Difference between NCEP's 20th Century daily Forecast and Analysis variables

NCEP's Twentieth Century Reanalysis (V2) provides daily variables from 1871/01/01 to 2012/12/31. Monolayer analysis variables are made available in a regular grid and forecast variables in a gaussian ...