Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Within the framework of the international field campaign COPS (Convective and Orographically induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. This includes networks of in situ and remote-sensing systems such as the Global Positioning System as well as a synergy of multi-wavelength passive and active remote-sensing instruments such as advanced radar and lidar systems. The COPS field phase was performed from 01 June to 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges mountains, the Rhine valley and the Black Forest mountains. The collected dataset covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase until their decay. Eighteen Intensive Observations Periods with 37 operation days and eight additional Special Observations Periods were performed, providing a comprehensive dataset covering different forcing conditions. In this article, an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS research provides new insight into key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of quantitative precipitation forecasting by the assimilation of new observations, and in the performance of ensembles of convection-permitting models in complex terrain.
ISSN: 0035-9009

hal-00565513
https://hal.archives-ouvertes.fr/hal-00565513
DOI : 10.1002/qj.752

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
An intensive water vapour intercomparison effort, involving airborne and ground-based water vapour lidar systems, was carried out in the framework of the COPS experiment. The main objective of this paper is to provide accurate error estimates for these systems. Comparisons between the ground-based Raman lidar BASIL and the airborne CNRS DIAL (Differential Absorption Lidar) indicate a mean relative bias between the two sensors, calculated with respect to the mean value of −2.13% (−0.034 g kg−1) in the altitude region 0.5-3.5 km, while comparisons between BASIL and the airborne DLR DIAL lead to a mean relative bias of 1.87% (0.018 g kg−1) in this same altitude region. Comparisons between the ground-based UHOH DIAL and the CNRS DIAL indicate a bias of −3.2% (−0.37 × 1022 m−3) in the altitude range 1.5-4.5 km, while comparisons between the UHOH DIAL and the DLR DIAL indicate a bias of 0.83% (0.06 × 1022 m−3) in this same altitude range. Based on the available comparisons between the ground-based Raman lidar BERTHA and the CNRS DIAL, the mean relative bias is found to be −4.37% (−0.123 g kg−1) in the altitude region 0.5-4.5 km. Comparisons between the ground-based IGN Raman lidar and the CNRS DIAL indicate a bias of 3.18% (0.55 g kg−1) in the altitude range from 0.5 to 4.5 km, while comparisons between the CNRS DIAL and DLR DIAL result in a mean relative bias of 3.93% (1.1 × 1022 m−3) in the altitude interval 0.5-4.0 km. Based on the available statistics of comparisons, benefiting from the fact that the CNRS DIAL was able to be compared with all other lidar systems, and putting equal weight on the data reliability of each instrument, overall relative values for BASIL, BERTHA, IGN Raman lidar, UHOH DIAL, DLR DIAL, and CNRS DIAL, with respect to the mean value, are found to be −0.38, −2.60, 4.90, −1.43, −2.23 and 1.72%, respectively.
ISSN: 0035-9009

hal-00572576
https://hal.archives-ouvertes.fr/hal-00572576
DOI : 10.1002/qj.697