Modifizierung des Niederschlags über urbanen Gebieten am Beispiel Berlin

2021 ◽  
Author(s):  
Klemens Barfus ◽  
Christian Bernhofer ◽  
Matthias Mauder
Keyword(s):  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Climate Zones ◽  
Local Climate ◽  
Local Climate Zones ◽  
Weather Research

<p>Vielzählige Beschreibungen vorwiegend aus dem nordamerikanischen Raum weisen auf einen Einfluss urbaner Gebiete auf den Niederschlag hin. Dabei sind die zugrundeliegenden Ursachen nicht hinlänglich geklärt.</p> <p>Eingebettet in das BMBF-ClimXtreme-Projekt wird im Rahmen der Studie der Einfluss urbaner Gebiete auf den Niederschlag am Beispiel Berlins untersucht. Dazu werden sowohl 5-Minuten/1km-Radardaten (YW-Produkt des Deutschen Wetterdienstes) als auch das mesoskalige Weather Research and Forecasting Model (WRF) verwendet. Rückgrat der Analysen ist ein Algorithmus zur Identifikation und zum Tracking hochreichender konvektiver Zellen. Indem der Algorithmus auf die Radardaten angewendet wurde, wurden Zelltracks für den Großraum Berlin im Zeitraum 2001 bis 2020 ermittelt.</p> <p>Entsprechend wurden Situationen identifiziert, in denen a.) Zellen über dem Stadtgebiet entstehen, während im Umland keine hochreichende Konvektion vorhanden ist, b.) Zellen bei der Überquerung Berlins über dem Stadtgebiet eine Verstärkung der Niederschlagsintensität und/oder Größenzunahme zeigen und c.) Zellen, die nach Überquerung des Stadtgebiets im Lee der eine verstärkte Niederschlagsintensität und/oder Größenzunahme zeigen.</p> <p>Für die einzelnen Fälle werden die atmosphärischen Bedingungen / mögliche Ursachen, wie Zirkulation, Stabilität, Urbane Wärmeinsel und Aerosolgehalt aus Messdaten (z.B. Stationen) und Modellen (ERA5) ermittelt. Weiterhin wird versucht entsprechende Effekte mit konvektionsauflösenden WRF-Simulationen (ERA5 als Input) nachzubilden. Hierbei wird der Einfluss der Stadtstruktur durch “Local Climate Zones” beschrieben, welche im Rahmen von Sensitivitätsanalysen variiert werden. Für entsprechende Vergleiche mit den Radardaten wird der Zellidentifizierungs- und trackingalgorithmus auch auf die WRF-Simulationen angewendet. </p>

scholarly journals Land-Use Improvements in the Weather Research and Forecasting Model over Complex Mountainous Terrain and Comparison of Different Grid Sizes

2021 ◽  
Author(s):  
Alessio Golzio ◽  
Silvia Ferrarese ◽  
Claudio Cassardo ◽  
Gugliemina Adele Diolaiuti ◽  
Manuela Pelfini
Keyword(s):  
Boundary Layer ◽  
Land Use ◽  
Land Cover ◽  
Mixing Layer ◽  
Local Area ◽  
Heat Fluxes ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Mountainous Terrain ◽  
Weather Research

AbstractWeather forecasts over mountainous terrain are challenging due to the complex topography that is necessarily smoothed by actual local-area models. As complex mountainous territories represent 20% of the Earth’s surface, accurate forecasts and the numerical resolution of the interaction between the surface and the atmospheric boundary layer are crucial. We present an assessment of the Weather Research and Forecasting model with two different grid spacings (1 km and 0.5 km), using two topography datasets (NASA Shuttle Radar Topography Mission and Global Multi-resolution Terrain Elevation Data 2010, digital elevation models) and four land-cover-description datasets (Corine Land Cover, U.S. Geological Survey land-use, MODIS30 and MODIS15, Moderate Resolution Imaging Spectroradiometer land-use). We investigate the Ortles Cevadale region in the Rhaetian Alps (central Italian Alps), focusing on the upper Forni Glacier proglacial area, where a micrometeorological station operated from 28 August to 11 September 2017. The simulation outputs are compared with observations at this micrometeorological station and four other weather stations distributed around the Forni Glacier with respect to the latent heat, sensible heat and ground heat fluxes, mixing-layer height, soil moisture, 2-m air temperature, and 10-m wind speed. The different model runs make it possible to isolate the contributions of land use, topography, grid spacing, and boundary-layer parametrizations. Among the considered factors, land use proves to have the most significant impact on results.

scholarly journals Dynamic Changes of Local Climate Zones in the Guangdong–Hong Kong–Macao Greater Bay Area and Their Spatio-Temporal Impacts on the Surface Urban Heat Island Effect between 2005 and 2015

2021 ◽  
Vol 13 (11) ◽  
pp. 6374
Author(s):  
Yang Lu ◽  
Jiansi Yang ◽  
Song Ma
Keyword(s):  
Hong Kong ◽  
Land Surface ◽  
Morphological Changes ◽  
Mapping Method ◽  
Heat Radiation ◽  
Climate Zones ◽  
Local Climate ◽  
Bay Area ◽  
Local Climate Zones ◽  
Urban Heat

Local climate zones (LCZs) emphasize the influence of representative geometric properties and surface cover characteristics on the local climate. In this paper, we propose a multi-temporal LCZ mapping method, which was used to obtain LCZ maps for 2005 and 2015 in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA), and we analyze the effects of LCZ changes in the GBA on land surface temperature (LST) changes. The results reveal that: (1) The accuracy of the LCZ mapping of the GBA for 2005 and 2015 is 85.03% and 85.28%, respectively. (2) The built type category showing the largest increase in area from 2005 to 2015 is LCZ8 (large low-rise), with a 1.01% increase. The changes of the LCZs also vary among the cities due to the different factors, such as the economic development level and local policies. (3) The area showing a warming trend is larger than the area showing a cooling trend in all the cities in the GBA study area. The main reasons for the warming are the increase of built types, the enhancement of human activities, and the heat radiation from surrounding high-temperature areas. (4) The spatial morphology changes of the built type categories are positively correlated with the LST changes, and the morphological changes of the LCZ4 (open high-rise) and LCZ5 (open midrise) built types exert the most significant influence. These findings will provide important insights for urban heat mitigation via rational landscape design in urban planning management.

Mapping local climate zones and their associated heat risk issues in Beijing: based on open data

2021 ◽  
pp. 103174
Author(s):  
Yi ZHOU ◽  
Guoliang ZHANG ◽  
Li JIANG ◽  
Xin CHEN ◽  
Tianqi XIE ◽  
...  
Keyword(s):  
Open Data ◽  
Climate Zones ◽  
Local Climate ◽  
Local Climate Zones ◽  
Heat Risk

Parallelization Strategies for the GPS Radio Occultation Data Assimilation with a Nonlocal Operator in the Weather Research and Forecasting Model

2014 ◽  
Vol 31 (9) ◽  
pp. 2008-2014 ◽  
Author(s):  
Xin Zhang ◽  
Ying-Hwa Kuo ◽  
Shu-Ya Chen ◽  
Xiang-Yu Huang ◽  
Ling-Feng Hsiao
Keyword(s):  
Data Assimilation ◽  
Radio Occultation ◽  
Weather Prediction ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Observation Operator ◽  
Gps Radio Occultation ◽  
Phase Observation ◽  
Excess Phase ◽  
Weather Research

Abstract The nonlocal excess phase observation operator for assimilating the global positioning system (GPS) radio occultation (RO) sounding data has been proven by some research papers to produce significantly better analyses for numerical weather prediction (NWP) compared to the local refractivity observation operator. However, the high computational cost and the difficulties in parallelization associated with the nonlocal GPS RO operator deter its application in research and operational NWP practices. In this article, two strategies are designed and implemented in the data assimilation system for the Weather Research and Forecasting Model to demonstrate the capability of parallel assimilation of GPS RO profiles with the nonlocal excess phase observation operator. In particular, to solve the parallel load imbalance problem due to the uneven geographic distribution of the GPS RO observations, round-robin scheduling is adopted to distribute GPS RO observations among the processing cores to balance the workload. The wall clock time required to complete a five-iteration minimization on a demonstration Antarctic case with 106 GPS RO observations is reduced from more than 3.5 h with a single processing core to 2.5 min with 106 processing cores. These strategies present the possibility of application of the nonlocal GPS RO excess phase observation operator in operational data assimilation systems with a cutoff time limit.

Simulations of Coastal Fog in the Canadian Atlantic with the Weather Research and Forecasting Model

2021 ◽  
Author(s):  
Reneta Dimitrova ◽  
Ashish Sharma ◽  
Harindra J. S. Fernando ◽  
Ismail Gultepe ◽  
Ventsislav Danchovski ◽  
...  
Keyword(s):  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Coastal Fog ◽  
Weather Research
Sign in / Sign up

Export Citation Format

Share Document