Submitted as: model evaluation paper
24 Mar 2021
Submitted as: model evaluation paper | 24 Mar 2021
Status: a revised version of this preprint was accepted for the journal GMD.

Assessment of stochastic weather forecast of precipitation near European cities, based on analogs of circulation

Meriem Krouma1,2, Pascal Yiou2, Céline Déandreis1, and Soulivanh Thao2 Meriem Krouma et al.
  • 1ARIA Technologies, 8 Rue de la Ferme, 92100 Boulogne-Billancourt, France
  • 2Laboratoire des Sciences du Climat et de l’Environnement, UMR 8212 CEA-CNRS-UVSQ, IPSL ’&’ Université Paris-Saclay, 91191 Gif-sur-Yvette, France

Abstract. In this study, we aim to assess the skill of a stochastic weather generator (SWG) to forecast precipitation in several cities of Western Europe. The SWG is based on random sampling of analogs of the geopotential height at 500 hPa. The SWG is evaluated for two reanalyses (NCEP and ERA5). We simulate 100-member ensemble forecasts on a daily time increment. We evaluate the performance of SWG with forecast skill scores and we compare it to ECMWF forecasts. Results show significant positive skill scores (continuous rank probability skill score and correlation) for lead times of 5 and 10 days for different areas in Europe. 

We found that the low predictability of our model is related to specific weather regimes, depending on the European region. Comparing SWG forecasts to ECMWF forecasts, we found that the SWG shows a good performance for 5 days.  This performance varies from one region to another. This paper is a proof of concept for a stochastic regional ensemble precipitation forecast. Its parameters (e.g. region for analogs) must be tuned for each region in order to optimize its performance.

Meriem Krouma et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on gmd-2021-36', Anonymous Referee #1, 20 Apr 2021
    • AC1: 'Reply on RC1', Meriem Krouma, 31 Jul 2021
  • RC2: 'Comment on gmd-2021-36', Anonymous Referee #2, 05 Jul 2021
    • AC2: 'Reply on RC2', Meriem Krouma, 31 Jul 2021

Meriem Krouma et al.

Data sets

Analogs of circulation Meriem Krouma

Model code and software

Code for forecast Meriem Krouma

Meriem Krouma et al.


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Short summary
We aim to evaluate the skill of a stochastic weather generator (SWG) to forecast precipitation at different time scales and in different areas of Western Europe from analogs of Z500 hPa. SWG has skill to simulate precipitation for 5 and 10 days. We found that forecast weaknesses can be associated with specific weather patterns. Comparing with ECMWF forecasts confirms the skill of our model. This work is important because it provides information about weather forecasts over specific areas.