Description: | A 12-month Standardized Precipitation Evapotranspiration Index (SPEI) was derived using precipitation depths and calculated potential evapotranspiration (PET) using the Thornthwaite method, which requires average temperature and latitude. The SPEI package in R was used for this derivation and was created by Santiago Begueria, Borja Latorre, Fergus Reig, and Sergio M. Vicente Serrano. Certain SPEI values for a few sites were interpolated for up to five months during some time series even though the temperature values were missing. We believe it is based on the 12-month SPEI time scale since it is longer than the missing data.
Missing data periods include the following sites and dates (YYYY-MM):
G-BASN: 2015-03, 2015-04, 2015-05, 2015-06, 2015-07
G-SUMM: 2015-04, 2015-05, 2015-06, 2015-07
M-NORT: 2014-06, 2014-07, 2014-8, 2014-09
M-WELL: 2014-07, 2014-08, 2014-09, 2015-03, 2015-04, 2015-05, 2015-06, 2015-07, 2015-08
P-COLL: 2014-06, 2014-07, 2014-08, 2014-09, 2015-03, 2015-04, 2015-05, 2015-06, 2015-07
P-TOBO: 2015-03, 2015-04, 2015-05, 2015-06, 2015-07, 2015-08, 2015-09
T-EAST: 2014-06, 2014-07, 2014-08, 2015-03, 2015-04, 2015-05, 2015-06, 2015-07
T-TAYL: 2014-07, 2014-08, 2015-03, 2015-04, 2015-05, 2015-06, 2015-07
T-WEST: 2015-03, 2015-04, 2015-05, 2015-06, 2015-07
S.M. Vicente-Serrano, S. Beguería, J.I. López-Moreno. 2010. A Multi-scalar drought index sensitive to global warming: The Standardized Precipitation Evapotranspiration Index – SPEI. Journal of Climate 23: 1696, DOI: 10.1175/2009JCLI2909.1. http://sac.csic.es/spei/ |