Observation datasets to validate simulations over Africa

 

This document provides little information about the available products to validate the RT3.5 RCM outputs from ENSEMBLES, their caveats, and the associated published papers.

Gridded datasets:

 

Dataset Name / Acronym

CRUTS2.1

Centre

Climate Research Unit (CRU)

Variables

Surface air temperature, Rainfall, DTR, Tmin, Tmax, cloud cover, vapour pressure, Number of frost / wet days.

Time period / scale

Monthly means – Jan 1901-Dec 2002

Resolution

Regular 0.5° grid (360 lat x 720 lon)

Lon=[-179.5-179.5]

Lat=[-89.75-89.75]

Format

ASCII (CRU website)

Download Link

http://www.cru.uea.ac.uk/cru/data/hrg/cru_ts_2.10/data_all/

Details /README

http://www.cru.uea.ac.uk/~timm/grid/CRU_TS_2_1.html

Reference paper

Mitchel T.D. and Jones P.D. (2005), An improved method of constructing a database of monthly climate observations and associated high-resolution grids,  Int. J. Climatol, {25}, 693--712.

Caveats / Comments

The missing values are replaced by the 1961-1990 climatology. As the number of available stations significantly decreased during the 1990s over West Africa, it could lead to problems in interpretation. The user can download the “station” files under

http://www.cru.uea.ac.uk/cru/data/hrg/cru_ts_2.10/stn_all/

To apply a consistent mask taking into account the missing values.

 

Dataset Name / Acronym

CMAP

Centre

CPC (Climate Prediction Centre) Merged Analysis of Precipitation

Variables

Precipitation

Time period / scale

Monthly and pentad (5 days) means

Jan 1979-Dec 2007

Resolution

Regular 2.5° grid (72 lat x 144 lon)

Lon=[-179.5-179.5]

Lat=[-89.75-89.75]

Format

netcdf (CDC website)

Download Link

http://www.cdc.noaa.gov/data/gridded/data.cmap.html

Details /README

http://www.cpc.noaa.gov/products/global_precip/html/wpage.cmap.html

Reference paper

Similar method than the one employed for GPCP

Huffman, G. J. and co-authors, 1997: The Global Precipitation Climatology Project (GPCP) combined data set. Bull. Amer. Meteor. Soc., 78, 5-20.

Acknowledgments:

Include text such as CMAP Precipitation data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.cdc.noaa.gov/ in any documents or publications using these data.

Caveats / Comments

None. With GPCP, one of the best gridded products to study climate variability over Africa for the RT3.5 period (1988-2006)

 

Dataset Name / Acronym

GPCP (v2)

Centre

The Global Precipitation Climatology Project (GPCP) was established by the World Climate Research Programme (WCRP) to quantify the distribution of precipitation around the globe over many years.

Variables

Precipitation / associated satellite measurements errors

Time period / scale

Monthly means, pentad (5 days) and daily means (1DD data)

 Jan 1979-Present (3 months before the actual date)

Oct 1996-Present (1DD dataset)

Resolution

GaussianT63  2.5° grid (96 lat x 192 lon) for monthly means and pentads

Regular 1°x1° grid (1DD dataset)

Format

ASCII and netcdf  

Download Links

http://lwf.ncdc.noaa.gov/oa/wmo/wdcamet-ncdc.html

http://precip.gsfc.nasa.gov/

http://jisao.washington.edu/data_sets/#precipitation_gridded_data_sets

(in a more compliant netcdf format)

Details /README

http://www.gewex.org/gpcpdata.htm

Reference paper

SG: Adler, R.F., G.J. Huffman, A. Chang, R. Ferraro, P. Xie, J. Janowiak, B. Rudolf, U. Schneider, S. Curtis, D. Bolvin, A. Gruber, J. Susskind, P. Arkin, 2003: The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present). J. Hydrometeor., 4,1147-1167.

Pentad: Xie, P., J.E. Janowiak, P.A. Arkin, R.F. Adler, A. Gruber, R.R. Ferraro, G.J. Huffman, S. Curtis, 2003: GPCP Pentad Precipitation Analyses: An Experimental Dataset Based on Gauge Observations and Satellite Estimates. J. of Climate, 16, 2197-2214.

1DD: Huffman, G.J., R.F. Adler, M. Morrissey, D.T. Bolvin, S. Curtis, R. Joyce, B McGavock, J. Susskind, 2001: Global Precipitation at One-Degree Daily Resolution from Multi-Satellite Observations. J. Hydrometeor., 2, 36-50.

Caveats / Comments

None.

 

Dataset Name / Acronym

NCEP Reanalysis

Centre

National Centers for Environmental Predictions (NCEP) and National Center for Atmospheric Research (NCAR).

Variables

Almost everything (reanalysis). Surface and Pressure level data (Fluxes etc)

Time period / scale

Daily and Monthly means

 Jan 1948-Present

Resolution

Regular 2.5° grid (73x144) Lat=[90S-90N] Lon=[0-357.5E] for most of the variables

T62 Gaussian grid (94x192) for flux dataset. 28 vertical levels

Format

netcdf (CDC website)

Download Link

http://www.cdc.noaa.gov/data/gridded/data.ncep.reanalysis.derived.html

Details /README

http://www.cdc.noaa.gov/data/gridded/data.ncep.reanalysis.derived.html#detail

Reference paper

Kalney E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha G, White G, Woolen J, Zhu Y, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Letmaa A, Reynolds R, Roy Jenne, Joseph D (1996) The NCEP / NCAR 40-year reanalysis project. Bull Amer Met

soc 17(3):437–471

 

Caveats / Comments

A limitation of the NCEP reanalysis in characterizing the low-frequency variability of the atmospheric circulation has been shown by Kinter et al (2004) over the tropics, and more specifically over Africa by Camberlin et al (2001) and Poccard et al (2000). This leads to problem in studying tropical climate variability before 1970 (before the satellite measurements are considered in the assimilation process). As the period of interest within RT3.5 ranges from 1988 to 2006 it is not a big issue.

Camberlin P, Janicot S, Poccard I (2001) Seasonality and atmospheric dynamics of the teleconnections between Africa and tropical ocean surface temperature: Atlantic vs ENSO, Int J Clim, 21: 973-1005.

Poccard I, Janicot S, Camberlin P (2000) Comparison of rainfall structures between NCEP-NCAR reanalysis and observed data over Africa, Clim Dyn, 16: 897-915.

Kinter J, Fennessy M, Krishnamurphy V, Marx L (2004) An evaluation of the Apparent interdecadal shift in the tropical divergent circulation in the NCEP-NCAR reanalysis, J Clim 17: 349-361.

 

Dataset Name / Acronym

ERA40 Reanalysis

Centre

European Centre for Medium-Range Weather Forecasts (ECMWF)

Variables

Almost everything (reanalysis). Surface and Pressure level data (Fluxes etc)

Time period / scale

Daily and Monthly means / 6 hours values

 Sept 1957-Aug 2002

Resolution

Regular 2.5° grid (73x144) Lat=[90S-90N] Lon=[0-357.5E] for most of the variables. 60 (28) vertical (pressure) levels

Format

netcdf (ECMWF website)

Download Link

http://data-portal.ecmwf.int/data/d/era40_moda/

Details /README

http://www.ecmwf.int/research/era/do/get/era-40

Reference paper

Uppala, S.M., Kållberg, P.W., Simmons, A.J., Andrae, U., da Costa Bechtold, V., Fiorino, M., Gibson, J.K., Haseler, J., Hernandez, A., Kelly, G.A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R.P., Andersson, E., Arpe, K., Balmaseda, M.A., Beljaars, A.C.M., van de Berg, L., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Hólm, E., Hoskins, B.J., Isaksen, L., Janssen, P.A.E.M., Jenne, R., McNally, A.P., Mahfouf, J.-F., Morcrette, J.-J., Rayner, N.A., Saunders, R.W., Simon, P., Sterl, A., Trenberth, K.E., Untch, A., Vasiljevic, D., Viterbo, P., and Woollen, J. 2005:

The ERA-40 re-analysis. Quart. J. R. Meteorol. Soc., 131, 2961-3012.doi:10.1256/qj.04.176

More details:

http://www.ecmwf.int/publications/library/do/references/list/192

 

 

Caveats / Comments

 

Concerning Rainfall, the ERA40 reanalysis exhibits a significant bias in the ITCZ migration and in its magnitude over West-Africa during summer and more generally over the Sahel (the ITCZ does not extend enough northward). There are big problems concerning surface variables in ERA40 over West Africa. However large scale dynamical features (TEJ / AEJ / WAMI) are relatively close to the NCEP ones after 1968 (seasonal time scale).

 

 

Dataset Name / Acronym

JRA-25  Reanalysis

Centre

The Japan Meteorological Agency (JMA) conducted the Japanese 25-year ReAnalysis (JRA-25) in collaboration with the Central Research Institute of Electric Power Industry (CRIEPI).

Variables

Almost everything (reanalysis). Surface and Pressure level data (Fluxes etc)

Time period / scale

Daily and Monthly means / 6 hours values

 Jan 1979-Dec 2004

Resolution

T106L40

Format

netcdf

Download Link

http://jra.kishou.go.jp/JRA-25/index_en.html

(need an access first)

Details /README

http://jra.kishou.go.jp/JRA-25/AboutJRA25_en.html

 

Reference paper

 

Onogi, K., J. Tsutsui, H. Koide, M. Sakamoto, S. Kobayashi, H. Hatsushika, T. Matsumoto, N. Yamazaki, H. Kamahori, K. Takahashi, S. Kadokura, K. Wada, K. Kato, R. Oyama, T. Ose, N. Mannoji and R. Taira (2007) : The JRA-25 Reanalysis. J. Meteor. Soc. Japan, 85, 369-432.

 

Caveats / Comments

Need to check the Japanese reanalysis reliability over West Africa.

 

 

Dataset Name / Acronym

ECMWF / AMMA Reanalysis for 2006

Centre

European Centre for Medium-Range Weather Forecasts (ECMWF)

Variables

Almost everything (reanalysis). Surface and Pressure level data (Fluxes etc)

Time period / scale

6 hours- 12 hours – daily and above

 01-01-2006 to 30-09-2006

Resolution

T511 (spectral fields), reduced N256 Gaussian grid (about 40km)

Regular 0.5° grid (100°W-50°E, 47°N-25°S) on the AMMA database

Format

netcdf / GRIB (ECMWF website)

Download Link

MARS archive system at ECMWF

http://catalogue.amma-international.org/ListDataset.do?datsTypeId=24

(AMMA database)

Details /README

http://bddamma.ipsl.polytechnique.fr/ecmwf-amma-re-analysis.html

Reference paper

https://www.amma-eu.org/workspaces/work_package_s_workspace/demonstration-training/wp5_1/deliverables/d5-1-d-ecmwf-amma-re/downloadFile/file/D51d.pdf?nocache=1235492991.5

 

Caveats / Comments

 

None

 

 

 

Station datasets:

 

Dataset Name / Acronym

GHCN v2 and GHCN

Centre

Global Historical Climatology Network (GHCN) from NCDC (National Climatic Data Center, USA)

Variables

Rainfall-Temperature

Time period / scale

Monthly and daily means – Jan 1900-most up to date

Resolution

Regular 5° grid (36 lat x 72 lon) / station values

Format

ASCII / netcdf

Download Link

ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v2/grid/ (gridded)

ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v2/ (stations)

ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/ (daily station)

Details /README

http://www.ncdc.noaa.gov/oa/climate/research/ghcn/ghcngrid-prcp.html

Reference paper

Check the NCDC data dissemination policy

Caveats / Comments

Used in several papers focusing on African Climate variability.

 

Dataset Name / Acronym

DCLIM

Centre

Donnees climatologiques historiques (Meteo-France)

Variables

Rainfall-Temperature-Tmin-Tmax

Time period / scale

Daily means – 1857-03-01 to 1983-12-31

Resolution

Station data

Format

ASCII

Download Link

http://catalogue.amma-international.org/EditDataset.do?datsId=148

(need an access to the AMMA database)

Details /README

http://catalogue.amma-international.org/EditDataset.do?datsId=148

 

Reference paper

Check the AMMA database dissemination policy

Caveats / Comments

Homogenised station data set. The time period does not fit the RT3.5 one, as most of the data are not available for the 1990s. Note that an extended station dataset (merging different sources) is available on the AMMA database

 

Dataset Name / Acronym

BADOPLU

Centre

Institut de Recherche pour le Developpement (IRD)

Variables

Rainfall-Temperature

Time period / scale

Daily means

Resolution

Station data

Format

ASCII

Download Link

Contact someone at IRD

Details /README

Contact someone at IRD

Reference paper

Check the AMMA /IRD database dissemination policy

Caveats / Comments

The data should be available on the AMMA database. You should check with someone at IRD to know the data dissemination policy.

 

Dataset Name / Acronym

MIDAS Land Surface Observation Stations Data

 

Centre

Met Office - UK

Variables

Rainfall-Temperature and others

Time period / scale

Daily / hourly and sub-hourly

Resolution

Station data / UK and global

Format

ASCII

Download Link

http://badc.nerc.ac.uk/data/ukmo-midas/

Details /README

http://badc.nerc.ac.uk/data/ukmo-midas/

Reference paper

Check the BADC / Met-Office  database dissemination policy

Caveats / Comments

An access to the BADC database is required.

 

More generally you can find useful information using this web addresses (the JISAO archive gives a clear overview and extra links to the other databases).


Climate Research Unit (CRU) Climate datasets
Met Office Hadley Centre observations datasets
British Atmospheric Data Center (BADC)
National Climatic Data Center (NCDC)
International Research Insititute for Climate and Society Data library (IRI)
Joint Institute for the Study of the Atmosphere and Ocean (JISAO)
AMMA Database