PRECIPITATION MINUS EVAPO-TRANSPIRATION(P-ET)(Bromwich, Serreze)

Overview

     This data set provides estimates of monthly P-ET based on
the so-called "aerological method" using wind and humidity data
from the NCEP/NCAR reanalysis [Kalnay et al., 1996]. P-ET
represents the vertically-integrated vapor flux convergence
adjusted by the time change in precipitable water. NCEP/NCAR
archives vertical integrals of the monthly-mean zonal and
meridional fluxes and precipitable water (based on 6-hourly
values at sigma levels), hence simplifying calculations.  The P-
ET fields are interpolated to the 25 km EASE grid.  Details of
the P-ET calculations and some climate applications are provided
by Cullather et al. [2000] and Serreze et al. [2003].  

Comments

     Like the NCEP/NCAR precipitation fields, the P-ET fields
contain a "blotchy" pattern.  This reflects shortcomings in the
NCEP/NCAR reanalysis system (see comments under DAILY
PRECIPITATION, FROM MONTHLY STATION RECORDS AND DISAGGREGATION).
The problem is mitigated, but not entirely eliminated, by
smoothing introduced when interpolating the P-ET data to the EASE
grid.

References   

Cullather, R.I., D.H. Bromwich, and M.C. Serreze, 2000: The
atmospheric hydrologic cycle over the Arctic basin from
reanalyses. Part I: Comparison with observations and previous
studies.  J. Climate, 13, 923-937

Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L.
Gandin, M. Iredell, S. Saha, G. White, J. Woolen, Y. Zhu, M.
Chelliah, W. Ebisuzaki, W. Higgens, J. Janowiak, K.C. Mo, C.
Ropelewski, J. Wang, A. Leetma, R. Reynolds, R. Jenne, and D.
Joseph, 1996: The NCEP/NCAR 40-year reanalysis project.  Bull.
Amer. Meteorol. Soc., 77, 437-471.

Serreze, M.C., D.H. Bromwich, M.P. Clark , A.J. Etringer, T.
Zhang and R. Lammers, 2003: The large-scale hydro-climatology of
the terrestrial Arctic drainage system. J. Geophys. Res. (in
press).