TY - GEN
AU - Antje Weisheimer
AU - T.N. Palmer
AB - Seasonal climate forecasts are being used increasingly across a range of application sectors. A recent UK governmental report asked: How good are seasonal forecasts on a scale of 1-5 (where 5 is very good), and how good can we expect them to be in 30 years time? Seasonal forecasts are made from ensembles of integrations of numerical models of climate. We argue that “goodness” should be assessed first and foremost in terms of the probabilistic reliability of these ensemble-based forecasts; reliable inputs are essential for any forecast-based decision making. We propose that a “5” should be reserved for systems which are not only reliable overall, but where, in particular, small ensemble spread is a reliable indicator of low ensemble forecast error. We study the reliability of regional temperature and precipitation forecasts of the current operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts, universally regarded as one of the world leading operational institutes producing seasonal climate forecasts. A wide range of “goodness” rankings, depending on region and variable (with summer forecasts of rainfall over Northern Europe performing exceptionally poorly) is found. Finally, we discuss the prospects of reaching “5” across all regions and variables in 30 years time.
BT - ECMWF Technical Memoranda
DA - 04/2014
DO - 10.21957/ku6twzpsk
LA - eng
M1 - 722
N2 - Seasonal climate forecasts are being used increasingly across a range of application sectors. A recent UK governmental report asked: How good are seasonal forecasts on a scale of 1-5 (where 5 is very good), and how good can we expect them to be in 30 years time? Seasonal forecasts are made from ensembles of integrations of numerical models of climate. We argue that “goodness” should be assessed first and foremost in terms of the probabilistic reliability of these ensemble-based forecasts; reliable inputs are essential for any forecast-based decision making. We propose that a “5” should be reserved for systems which are not only reliable overall, but where, in particular, small ensemble spread is a reliable indicator of low ensemble forecast error. We study the reliability of regional temperature and precipitation forecasts of the current operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts, universally regarded as one of the world leading operational institutes producing seasonal climate forecasts. A wide range of “goodness” rankings, depending on region and variable (with summer forecasts of rainfall over Northern Europe performing exceptionally poorly) is found. Finally, we discuss the prospects of reaching “5” across all regions and variables in 30 years time.
PB - ECMWF
PY - 2014
EP - 17
T2 - ECMWF Technical Memoranda
TI - On the reliability of seasonal climate forecasts
UR - https://www.ecmwf.int/node/13050
ER -