Detection of land-surface-induced atmospheric water vapor patterns

Marke, Tobias; Löhnert, Ulrich; Schemann, Vera; Schween, Jan H.; Crewell, Susanne

doi:10.5194/acp-20-1723-2020

Cited by 5 publications

(7 citation statements)

References 41 publications

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“…For detection of land surface induced atmospheric water vapor patterns, Marke et al (2020) used passive MW measurements by the HATPRO radiometer in zenith direction and in azimuth scanning mode at the elevation angle of 30°.…”

Section: Data Samplingmentioning

confidence: 99%

“…This interval is similar to the interval in our study. However, it should be specially noted that Marke et al (2020) investigated only clear sky cases without any considerable advection.…”

Section: Data Samplingmentioning

confidence: 99%

“…First of all, we note that when azimuth scans at different elevation angles are performed the directional dependent interference can be present in measured signal. For example, Marke et al (2020) registered such interference in the unprotected 26.24 GHz channel at four specific azimuth directions. Corresponding measurements were filtered out and missing values were filled with linear interpolation.…”

Section: Systematic Component Of Signalmentioning

confidence: 99%

“…This territory is covered by the forest (park). In the study by Marke et al (2020) devoted to land surface induced atmospheric water vapor patterns, it has been shown that less water vapour seems to be present at elevated deciduous forest. In our case the forest is not elevated, however one can not expect a pattern of extra humidity over the forest.…”

Section: Systematic Component Of Signalmentioning

confidence: 99%

“…Stahli et al (2011) have proposed an imaging method for both water vapour and liquid clouds which used ground-based observations by the SPIRA ground-based MW radiometer operating at 91 GHz by continuously scanning the sky over a range of elevation angles in a fixed azimuth direction. Marke et al (2020) studied the influence of a heterogeneous land surface on the spatial distribution of atmospheric water vapor: they used ground-based remote sensing measurements of integrated water vapour (IWV) by a microwave radiometer HATPRO during clear sky conditions at 30° elevation angle (full azimuth scans with 10° step).…”

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confidence: 99%

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Detection of the cloud liquid water path horizontal inhomogeneity in a coastline area by means of ground-based microwave observations: feasibility study

Kostsov¹,

Ionov²,

Kniffka³

2020

Preprint

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Abstract. The improvement of cloud modelling for global and regional climate and weather studies requires comprehensive information on many cloud parameters. This information is delivered by remote observations of clouds from ground-based and space-borne platforms using different methods and processing algorithms. Cloud liquid water path (LWP) is one of the main obtained quantities. Previously, the measurements of LWP by the SEVIRI and AVHRR satellite instruments provided the evidences of the systematic differences between LWP values over land and water areas in Northern Europe. An attempt is made to detect such differences by means of ground-based microwave observations performed near the coastline of the Gulf of Finland in the vicinity of St. Petersburg, Russia. The microwave radiometer RPG HATPRO located 2.5 km from the coastline is functioning in the angular scanning mode and is probing the air portions over land (at elevation angle 90°) and over water area (at 7 elevation angles in the range 4.8°–30°). The problem of the LWP horizontal gradient detection is examined in the measurement domain: the brightness temperatures of the microwave radiation measured at different elevation angles in the 31.4 GHz and 22.24 GHz spectral channels are analysed and compared with the corresponding values which were calculated under the assumption of horizontal homogeneity of the atmosphere. Several specific cases, selected on the basis of the analysis of the satellite observations by the SEVIRI instrument were considered in detail including: clear-sky conditions, the presence of clouds over the radiometer and at the same time the absence of clouds over the Gulf of Finland, and overcast conditions over the radiometer and over the opposite shore of the Gulf of Finland. The influence of the land-sea LWP difference on the brightness temperature values in the 31.4 GHz spectral channel has been demonstrated and the following features have been detected: (1) an interfering systematic signal is present in the 31.4 GHz channel which can attributed to the humidity horizontal gradient; (2) clouds over the opposite shore of the Gulf of Finland mask the LWP gradient effect. Preliminary results of the retrieval of LWP over water by statistical regression method are presented. These monthly averaged results are compared to the corresponding values derived from the satellite observations by the SEVIRI instrument. The agreement between satellite and ground-based results is very good for warm season in terms of temporal behaviour if systematic difference is neglected.

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Section: Data Samplingmentioning

confidence: 99%

“…This interval is similar to the interval in our study. However, it should be specially noted that Marke et al (2020) investigated only clear sky cases without any considerable advection.…”

Section: Data Samplingmentioning

confidence: 99%

Section: Systematic Component Of Signalmentioning

confidence: 99%

Section: Systematic Component Of Signalmentioning

confidence: 99%

mentioning

confidence: 99%

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Detection of the cloud liquid water path horizontal inhomogeneity in a coastline area by means of ground-based microwave observations: feasibility study

Kostsov¹,

Ionov²,

Kniffka³

2020

Preprint

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Evolution of the Convective Boundary Layer in a WRF Simulation Nested Down to 100 m Resolution During a Cloud‐Free Case of LAFE, 2017 and Comparison to Observations

et al. 2023

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The Weather Research and Forecasting model was applied in a nested configuration from the convection‐permitting resolution of 2.5 km, via an intermediate resolution of 500 m down to the 100 m turbulence‐permitting scale to investigate the spatial and temporal evolution of the convective boundary layer and their interaction with the underlying land surface. This included detailed comparisons with observations collected during the Land‐Atmosphere Feedback Experiment, performed at the Central Facility in Oklahoma. The simulation was driven by the operational analysis of the European Center for Medium‐range Weather Forecasting for a cloud‐free case on 23 August 2017 for which the measurement operation was extended into the following night to include the evening decay of the daytime convective boundary layer. The mesoscale 2.5 km resolution was capable to represent the correct boundary layer height and its temporal evolution. Details of the morning and evening transitions between the nighttime and daytime boundary layer as well as its internal structure were only simulated by the 100 m turbulence‐permitting simulation. Although systematic differences between the simulation and lidar observations were found, the model captured the temporal and spatial structure and the statistics of turbulence rather well. Comparison with data from Eddy‐Covariance stations showed that the model was able to reproduce the evolution of many near‐surface meteorological fields. Systematically higher surface temperatures and related differences in the surface fluxes suggest weaknesses in the representation of land surface processes although the simulation was initialized with accurate and high‐resolution initial fields.

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The impact of urban land-surface on extreme air pollution over central Europe

et al. 2020

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Abstract. This paper deals with the urban land-surface impact (i.e., the urban canopy meteorological forcing; UCMF) on extreme air pollution for selected central European cities for present-day climate conditions (2015–2016) using three regional climate-chemistry models: the regional climate models RegCM and WRF-Chem (its meteorological part), the chemistry transport model CAMx coupled to either RegCM and WRF and the “chemical” component of WRF-Chem. Most of the studies dealing with the urban canopy meteorological forcing on air pollution focused on change in average conditions or only on a selected winter and/or summer air pollution episode. Here we extend these studies by focusing on long-term extreme air pollution levels by looking at not only the change in average values, but also their high (and low) percentile values, and we combine the analysis with investigating selected high-pollution episodes too. As extreme air pollution is often linked to extreme values of meteorological variables (e.g., low planetary boundary layer height, low winds, high temperatures), the urbanization-induced extreme meteorological modifications will be analyzed too. The validation of model results show reasonable model performance for regional-scale temperature and precipitation. Ozone is overestimated by about 10–20 µg m−3 (50 %–100 %); on the other hand, extreme summertime ozone values are underestimated by all models. Modeled nitrogen dioxide (NO2) concentrations are well correlated with observations, but results are marked by a systematic underestimation up to 20 µg m−3 (−50 %). PM2.5 (particles with diameter ≤2.5 µm) are systematically underestimated in most of the models by around 5 µg m−3 (50 %–70 %). Our results show that the impact on extreme values of meteorological variables can be substantially different from that of the impact on average ones: low (5th percentile) temperature in winter responds to UCMF much more than average values, while in summer, 95th percentiles increase more than averages. The impact on boundary layer height (PBLH), i.e., its increase is stronger for thicker PBLs and wind speed, is reduced much more for strong winds compared to average ones. The modeled changes in ozone (O3), NO2 and PM2.5 show the expected pattern, i.e., increase in average 8 h O3 up to 2–3 ppbv, decrease in daily average NO2 by around 2–4 ppbv and decrease in daily average PM2.5 by around −2 µg m−3. Regarding the impact on extreme (95th percentile) values of these pollutants, the impact on ozone at the high end of the distribution is rather similar to the impact on average 8 h values. A different picture is obtained however for extreme values of NO2 and PM2.5. The impact on the 95th percentile values is almost 2 times larger than the impact on the daily averages for both pollutants. The simulated impact on extreme values further well corresponds to the UCMF impact simulated for the selected high-pollution episodes. Our results bring light to the principal question: whether extreme air quality is modified by urban land surface with a different magnitude compared to the impact on average air pollution. We showed that this is indeed true for NO2 and PM2.5, while in the case of ozone, our results did not show substantial differences between the impact on mean and extreme values.

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Detection of land-surface-induced atmospheric water vapor patterns

Cited by 5 publications

References 41 publications

Detection of the cloud liquid water path horizontal inhomogeneity in a coastline area by means of ground-based microwave observations: feasibility study

Detection of the cloud liquid water path horizontal inhomogeneity in a coastline area by means of ground-based microwave observations: feasibility study

Evolution of the Convective Boundary Layer in a WRF Simulation Nested Down to 100 m Resolution During a Cloud‐Free Case of LAFE, 2017 and Comparison to Observations

The impact of urban land-surface on extreme air pollution over central Europe

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