Abstract. Future sea surface temperature and sea-ice concentration from coupled
ocean–atmosphere general circulation models such as those from the CMIP5
experiment are often used as boundary forcings for the downscaling of future
climate experiments. Yet, these models show some considerable biases when
compared to the observations over present climate. In this paper, existing
methods such as an absolute anomaly method and a quantile–quantile method
for sea surface temperature (SST) as well as a look-up table and a relative
anomaly method for sea-ice concentration (SIC) are presented. For SIC, we
also propose a new analogue method. Each method is objectively evaluated with
a perfect model test using CMIP5 model experiments and some real-case
applications using observations. We find that with respect to other
previously existing methods, the analogue method is a substantial improvement
for the bias correction of future SIC. Consistency between the constructed
SST and SIC fields is an important constraint to consider, as is consistency
between the prescribed sea-ice concentration and thickness; we show that the
latter can be ensured by using a simple parameterisation of sea-ice thickness
as a function of instantaneous and annual minimum SIC.
SEMI QUANTITATIVE PRECIPITATION FORECASTS FOR GHAGHRA CATCHMENT BY SYNOPTIC ANALOGUE METHOD
