Lat­est ver­sion: V2.2 (released March 2, 2018)

Mul­ti-Source Weight­ed-Ensem­ble Pre­cip­i­ta­tion (MSWEP) is a new ful­ly glob­al his­toric pre­cip­i­ta­tion dataset (1979–2017) with a 3-hourly tem­po­ral and 0.1° spa­tial res­o­lu­tion.

Why use MSWEP?

1. MSWEP takes advan­tage of the com­ple­men­tary strengths of gauge-, satel­lite-, and reanaly­sis-based data to pro­vide reli­able pre­cip­i­ta­tion esti­mates over the entire globe.
2. In two com­pre­hen­sive large-scale eval­u­a­tions, MSWEP per­formed best over­all (Beck et al., 2017; Beck et al., 2018).
3. Tru­ly glob­al cov­er­age (includ­ing ocean areas) at 3-hourly 0.1° res­o­lu­tion (oth­er satel­lite-based datasets, such as TMPA 3B42, are lim­it­ed to lat­i­tudes <50/60°).
4. Con­sis­tent pre­cip­i­ta­tion record from 1979 until the near present, enabling trend and drought assess­ments.
5. Dai­ly (rather than month­ly) gauge cor­rec­tions using obser­va­tions from ~77,000 sta­tions across the globe.
6. When apply­ing the dai­ly gauge cor­rec­tions, MSWEP accounts for dif­fer­ences in gauge report­ing times.
7. Cor­rec­tion of sys­tem­at­ic ter­res­tri­al pre­cip­i­ta­tion bias­es using riv­er dis­charge obser­va­tions from 13,762 sta­tions across the globe.

Val­i­da­tion

MSWEP has been part of two com­pre­hen­sive eval­u­a­tion stud­ies. In the first, 22 grid­ded pre­cip­i­ta­tion datasets were val­i­dat­ed using obser­va­tions from ~70,000 gauges and hydro­log­i­cal mod­el­ing for ~9000 catch­ments glob­al­ly:

• Beck, H. E., N. Ver­gopolan, M. Pan, V. Lev­iz­zani, A.I.J.M. van Dijk, G.P. Wee­don, L. Broc­ca, F. Pap­pen­berg­er, G.J. Huff­man, and E.F. Wood: Glob­al-scale eval­u­a­tion of 22 pre­cip­i­ta­tion datasets using gauge obser­va­tions and hydro­log­i­cal mod­el­ing, Hydrol­o­gy and Earth Sys­tem Sci­ences, 21(12), 6201–6217, 2017.

In the sec­ond, 26 pre­cip­i­ta­tion datasets were eval­u­at­ed using Stage-IV gauge-radar data for the CONUS:

• Beck, H. E., Pan, M., Roy, T., Wee­don, G. P., Pap­pen­berg­er, F., van Dijk, A. I. J. M., Huff­man, G. J., Adler, R. F., and Wood, E. F.: Dai­ly eval­u­a­tion of 26 pre­cip­i­ta­tion datasets using Stage-IV gauge-radar data for the CONUS, Hydrol. Earth Syst. Sci. Dis­cuss., in review, 2018.

Method­ol­o­gy

MSWEP opti­mal­ly merges a wide range of gauge, satel­lite, and reanaly­sis data to pro­vide reli­able pre­cip­i­ta­tion esti­mates over the entire globe. See the fol­low­ing paper for a detailed descrip­tion of the MSWEP V2 method­ol­o­gy:

• Beck, H. E., Wood, E. F., Pan, M., Fish­er, C. K., Miralles, D. M., van Dijk, A. I. J. M., McVicar, T. R., and Adler, R. F.: MSWEP V2 glob­al 3-hourly 0.1° pre­cip­i­ta­tion: method­ol­o­gy and quan­ti­ta­tive assess­ment, Bul­letin of the Amer­i­can Mete­o­ro­log­i­cal Soci­ety, in press, 2019.

The fol­low­ing paper describes the MSWEP V1 method­ol­o­gy:

• Beck, H.E., A.I.J.M. van Dijk, V. Lev­iz­zani, J. Schellekens, D.G. Miralles, B. Martens, A. de Roo: MSWEP: 3-hourly 0.25° glob­al grid­ded pre­cip­i­ta­tion (1979–2015) by merg­ing gauge, satel­lite, and reanaly­sis data, Hydrol­o­gy and Earth Sys­tem Sci­ences, 21(1), 589–615, 2017.

The most impor­tant changes in V2 com­pared to V1 include: (i) the intro­duc­tion of cumu­la­tive dis­tri­b­u­tion func­tion and pre­cip­i­ta­tion fre­quen­cy cor­rec­tions, to account for spu­ri­ous driz­zle and atten­u­at­ed peaks evi­dent in V1; (ii) increas­ing spa­tial res­o­lu­tion from 0.25° to 0.1° to increase the local rel­e­vance of the pre­cip­i­ta­tion esti­mates (espe­cial­ly impor­tant for high water-yield moun­tain­ous regions); (iii) the inclu­sion of ocean areas to enable ocean­ic stud­ies and ter­res­tri­al hydrol­o­gy stud­ies for coastal areas and small islands; (iv) the addi­tion of pre­cip­i­ta­tion esti­mates derived from Grid­ded Satel­lite (Grid­Sat) ther­mal infrared imagery for the pre-TRMM era to sup­ple­ment the reanaly­sis and gauge data; (v) the use of a dai­ly (rather than month­ly) gauge cor­rec­tion scheme that accounts for region­al dif­fer­ences in report­ing times, to min­i­mize tim­ing mis­match­es when apply­ing the dai­ly gauge cor­rec­tions; (vi) the use of a large data­base of dai­ly gauge obser­va­tions com­piled from sev­er­al sources to replace the 0.5° CPC Uni­fied dataset; and (vii) exten­sion of the data record to 2017 (MSWEP V1 fin­ished in 2016).

See the tech­ni­cal doc­u­men­ta­tion for the com­plete ver­sion his­to­ry.

Data access

For access to MSWEP, please send Hylke Beck a mes­sage includ­ing a project sum­ma­ry and a list of all your affil­i­a­tions (both aca­d­e­m­ic and com­mer­cial). Also spec­i­fy whether you intend to use the dataset for aca­d­e­m­ic or com­mer­cial pur­pos­es.

Acknowl­edge­ments

MSWEP is being devel­oped by Hylke Beck (Prince­ton Uni­ver­si­ty, Prince­ton, NJ, USA). The pre­cip­i­ta­tion dataset devel­op­ers are grate­ful­ly acknowl­edged for pro­duc­ing and mak­ing avail­able their datasets. The work was sup­port­ed through IPA sup­port from the U.S. Army Corps of Engi­neers’ Inter­na­tion­al Cen­ter for Inte­grat­ed Water Resources Man­age­ment (ICI­WaRM), under the aus­pices of UNESCO. By using MSWEP in any pub­li­ca­tion you agree to cite Beck et al. (2019).