Near Real Time GPS Water Vapor Monitoring for Numerical Weather Prediction in Germany

Gendt, G.; Dick, Galina; Reigber, Christoph; Tomassini, M.; Liu, Yanping; Ramatschi, Markus

doi:10.2151/jmsj.2004.361

Cited by 220 publications

(191 citation statements)

References 10 publications

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“…The values are small in all situations and lie inside the GPS uncertainty of 1-2 kg m −2 (Gendt et al, 2004) and the MWR product of ∼ 0.5-1 kg m −2 (Steinke et al, 2015). While the only-MWR case presents a negative bias of ∼ 0.5 kg m −2 , the inclusion of the RL in the RL+MWR case corrects this bias, reducing it 1 order of magnitude.…”

Section: Integrated Water Vapormentioning

confidence: 76%

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

et al. 2016

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Abstract. Continuous monitoring of atmospheric humidity profiles is important for many applications, e.g., assessment of atmospheric stability and cloud formation. Nowadays there are a wide variety of ground-based sensors for atmospheric humidity profiling. Unfortunately there is no single instrument able to provide a measurement with complete vertical coverage, high vertical and temporal resolution and good performance under all weather conditions, simultaneously. For example, Raman lidar (RL) measurements can provide water vapor with a high vertical resolution, albeit with limited vertical coverage, due to sunlight contamination and the presence of clouds. Microwave radiometers (MWRs) receive water vapor information throughout the troposphere, though their vertical resolution is poor. In this work, we present an MWR and RL system synergy, which aims to overcome the specific sensor limitations. The retrieval algorithm combining these two instruments is an optimal estimation method (OEM), which allows for an uncertainty analysis of the retrieved profiles. The OEM combines measurements and a priori information, taking the uncertainty of both into account. The measurement vector consists of a set of MWR brightness temperatures and RL water vapor profiles. The method is applied to a 2-month field campaign around Jülich (Germany), focusing on clear sky periods. Different experiments are performed to analyze the improvements achieved via the synergy compared to the individual retrievals. When applying the combined retrieval, on average the theoretically determined absolute humidity uncertainty is reduced above the last usable lidar range by a factor of ∼ 2 with respect to the case where only RL measurements are used. The analysis in terms of degrees of freedom per signal reveal that most information is gained above the usable lidar range, especially important during daytime when the lidar vertical coverage is limited. The retrieved profiles are further evaluated using radiosounding and Global Position Satellite (GPS) water vapor measurements. In general, the benefit of the sensor combination is especially strong in regions where Raman lidar data are not available (i.e., blind regions, regions characterized by low signal-to-noise ratio), whereas if both instruments are available, RL dominates the retrieval. In the future, the method will be extended to cloudy conditions, when the impact of the MWR becomes stronger.

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Section: Integrated Water Vapormentioning

confidence: 76%

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

et al. 2016

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“…GPS processing systems (e.g. Dick et al, 2001;Gendt et al, 2004) estimated several atmospheric parameters, such as STD, ZTD, and IWV under all weather conditions. STD data were available within short processing times for real-time data assimilation (Zus et al, 2008;Bauer et al, 2010).…”

Section: Network and Mobile Teamsmentioning

confidence: 99%

The Convective and Orographically‐induced Precipitation Study (COPS): the scientific strategy, the field phase, and research highlights

Wulfmeyer

Behrendt

Kottmeier

et al. 2011

Quart J Royal Meteoro Soc

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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 data set 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 Observation Periods with 37 operation days and eight additional Special Observation Periods were performed, providing a comprehensive data set 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.

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“…After collecting the data of GPS stations which were operated off-line and getting access to observations from other GPS providers not related to COPS, the total number of stations could be increased to more than 370 whereof 48 are located in the COPS region. These data were reprocessed by the GFZ using the GPS processing software EPOS (Gendt et al, 2004). To derive IWV, further surface meteorological observations are required (Dick et al, 2001).…”

Section: Gps-derived Integrated Water Vapourmentioning

confidence: 99%

Observation of convection initiation processes with a suite of state‐of‐the‐art research instruments during COPS IOP 8b

Behrendt

Pal

Aoshima

et al. 2011

Quart J Royal Meteoro Soc

106

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In the afternoon of 15 July 2007, a thunderstorm was initiated within a line of cumulus clouds which formed parallel to the crest of the Black Forest mountains during the Intensive Observation Period (IOP) 8b of the Convective and Orographicallyinduced Precipitation Study (COPS). This paper extends the analysis of processes that led to convection initiation (CI), i.e. the transition from shallow to deep convection, on this day with the data from several COPS instruments that have not been considered in previous studies. In particular, the boundary-layer structure, lids and the water-vapour field in the pre-convective environment of the event are discussed. For this purpose, we investigated measurements of water-vapour lidars, temperature lidars and wind lidars, profiles from radiosondes, in situ aircraft data and gridded data of weather stations as well as GPS integrated-water-vapour data and satellite imagery. Thermally driven circulation systems formed over both the Black Forest and the Vosges mountain ranges which resulted in local convergence zones. These superimposed with the large-scale convergence in the Black Forest area. In the presence of sufficient moisture and updraught, clouds formed close to the mountain crests. The related latent-heat release allowed larger thermals to be produced, which may have had a positive feedback on stabilizing these convergence zones as a whole. We believe that differences in the moisture field explain why convection remained shallow and sparse over the Vosges mountains because these differences were responsible for differences in convective inhibition (CIN). The stationary location of the convergence zone over the southern Black Forest was probably decisive for CI because it constantly transported sensible and latent heat into the area in which CI took place.

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Near Real Time GPS Water Vapor Monitoring for Numerical Weather Prediction in Germany

Cited by 220 publications

References 10 publications

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

The Convective and Orographically‐induced Precipitation Study (COPS): the scientific strategy, the field phase, and research highlights

Observation of convection initiation processes with a suite of state‐of‐the‐art research instruments during COPS IOP 8b

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