scholarly journals Assessing the Impact of Enhanced Hydrological Processes on Urban Hydrometeorology with Application to Two Cities in Contrasting Climates

2016 ◽  
Vol 17 (4) ◽  
pp. 1031-1047 ◽  
Author(s):  
Jiachuan Yang ◽  
Zhi-Hua Wang ◽  
Matei Georgescu ◽  
Fei Chen ◽  
Mukul Tewari
Keyword(s):  
Water Cycle ◽  
Wrf Model ◽  
Single Layer ◽  
Urban Canopy ◽  
Field Measurements ◽  
Green Roofs ◽  
The United States ◽  
Climatic Conditions ◽  
Hydrological Processes ◽  
The Impact

Abstract To enhance the capability of models in better characterizing the urban water cycle, physical parameterizations of urban hydrological processes have been implemented into the single-layer urban canopy model in the widely used Weather Research and Forecasting (WRF) Model. While the new model has been evaluated offline against field measurements at various cities, its performance in online settings via coupling to atmospheric dynamics requires further examination. In this study, the impact of urban hydrological processes on regional hydrometeorology of the fully integrated WRF–urban modeling system for two major cities in the United States, namely, Phoenix and Houston, is assessed. Results show that including hydrological processes improves prediction of the 2-m dewpoint temperature, an indicative measure of coupled thermal and hydrological processes. The implementation of green roof systems as an urban mitigation strategy is then tested at the annual scale. The reduction of environmental temperature and increase of humidity by green roofs indicate strong diurnal and seasonal variations and are significantly affected by geographical and climatic conditions. Comparison with offline studies reveals that land–atmosphere interactions play a crucial role in determining the effect of green roofs.

scholarly journals Relative Role of Turbulent and Radiative Flux on the Near-Surface Temperature in a Single-Layer Urban Canopy Model over Houston

2017 ◽  
Vol 56 (8) ◽  
pp. 2173-2187 ◽  
Author(s):  
James Brownlee ◽  
Pallav Ray ◽  
Mukul Tewari ◽  
Haochen Tan
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Single Layer ◽  
Urban Canopy ◽  
Heat Fluxes ◽  
Radiative Flux ◽  
Hydrological Processes ◽  
Urban Canopy Model ◽  
Near Surface ◽  
Canopy Model

AbstractNumerical simulations without hydrological processes tend to overestimate the near-surface temperatures over urban areas. This is presumably due to underestimation of surface latent heat flux. To test this hypothesis, the existing single-layer urban canopy model (SLUCM) within the Weather Research and Forecasting Model is evaluated over Houston, Texas. Three simulations were conducted during 24–26 August 2000. The simulations include the use of the default “BULK” urban scheme, the SLUCM without hydrological processes, and the SLUCM with hydrological processes. The results show that the BULK scheme was least accurate, and it overestimated the near-surface temperatures and winds over the urban regions. In the presence of urban hydrological processes, the SLUCM underestimates these parameters. An analysis of the surface heat fluxes suggests that the error in the BULK scheme is due to a lack of moisture at the urban surface, whereas the error in the SLUCM with hydrological processes is due to increases in moisture at the urban surface. These results confirm earlier studies in which changes in near-surface temperature were primarily due to the changes in the turbulent (latent and sensible heat) fluxes in the presence of hydrological processes. The contribution from radiative flux was about one-third of that from turbulent flux. In the absence of hydrological processes, however, the results indicate that the changes in radiative flux contribute more to the near-surface temperature changes than the turbulent heat flux. The implications of these results are discussed.

Assessing the Impact of Urban Hydrological Processes on the Summertime Urban Climate in Nanjing Using the WRF Model

2019 ◽  
Vol 124 (23) ◽  
pp. 12683-12707 ◽  
Author(s):  
Xueyuan Wang ◽  
Shiguang Miao ◽  
Hongnian Liu ◽  
Jianning Sun ◽  
Ning Zhang ◽  
...  
Keyword(s):  
Urban Climate ◽  
Wrf Model ◽  
Hydrological Processes ◽  
The Impact

scholarly journals Response of Near-Surface Meteorological Conditions to Advection under Impact of the Green Roof

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 759
Author(s):  
Haochen Tan ◽  
Pallav Ray ◽  
Mukul Tewari ◽  
James Brownlee ◽  
Ajaya Ravindran
Keyword(s):  
Surface Temperature ◽  
Urban Areas ◽  
Green Roof ◽  
Wrf Model ◽  
Single Layer ◽  
Meteorological Conditions ◽  
Rapid Urbanization ◽  
Near Surface ◽  
Budget Analysis ◽  
The Impact

Due to rapid urbanization, the near-surface meteorological conditions over urban areas are greatly modulated. To capture such modulations, sophisticated urban parameterizations with enhanced hydrological processes have been developed. In this study, we use the single-layer urban canopy model (SLUCM) available within the Weather Research and Forecasting (WRF) model to assess the response of near-surface temperature, wind, and moisture to advection under the impact of the green roof. An ensemble of simulations with different planetary boundary layer (PBL) schemes is conducted in the presence (green roof (GR)) and absence (control (CTL)) of green roof systems. Our results indicate that the near-surface temperature is found to be driven primarily by the surface heat flux with a minor influence from the zonal advection of temperature. The momentum budget analysis shows that both zonal and meridional momentum advection during the evening and early nighttime plays an important role in modulating winds over urban areas. The near-surface humidity remains nearly unchanged in GR compared to CTL, although the physical processes that determine the changes in humidity were different, in particular during the evening when the GR tends to have less moisture advection due to the reduced temperature gradient between the urban areas and the surroundings. Implications of our results are discussed.

Simulation of Downstream Effects of Urbanization on Cloud and Precipitation with WRF Model in Yangtze River Delta, China

2020 ◽  
Author(s):  
Xiaomen Han ◽  
Jianning Sun
Keyword(s):  
Yangtze River ◽  
Vertical Mixing ◽  
Wrf Model ◽  
Single Layer ◽  
Urban Canopy ◽  
Yangtze River Delta ◽  
River Delta ◽  
Dominant Factor ◽  
Urbanization Effect ◽  
Downstream Effects

<p>Urbanization, one of the extreme cases of land-use change, plays an important role in modifying precipitation and urban hydrology. In this study, urbanization effect on cloud and precipitation in the Yangtze River Delta of China is simulated using Weather Research and Forecasting (WRF) model coupled with a single-layer Urban Canopy Model(SLUCM). Based on the 4-summer simulation results from 2011 to 2014, we find that the influence of cities on clouds and precipitation is obviously affected by wind field. During the day, more cloud on higher level and precipitation occurs in urban area and downwind region of urban, induced by more unstable urban air transported downstream, which enhances vertical mixing and updraft moisture transport. At night, the urban dry island become the dominant factor, resulting in the decrease of cloud occurrence in the urban and downstream areas. The downstream effects of urbanization on cloud and precipitation turn out to be strongly related to the moisture and convective conditions.</p><p> </p>

Sensitivity of Predictions of the Urban Surface Energy Balance and Heat Island to Variations of Urban Canopy Parameters in Simulations with the WRF Model

2017 ◽  
Vol 56 (3) ◽  
pp. 573-595 ◽  
Author(s):  
Kodi L. Nemunaitis-Berry ◽  
Petra M. Klein ◽  
Jeffrey B. Basara ◽  
Evgeni Fedorovich
Keyword(s):  
Climate Models ◽  
Wrf Model ◽  
Single Layer ◽  
Urban Canopy ◽  
Heat Fluxes ◽  
Urban Air ◽  
Near Surface ◽  
Air Temperatures ◽  
Oklahoma Mesonet ◽  
Joint Urban 2003 Experiment

AbstractAs NWP and climate models continue to evolve toward finer grid spacing, efforts have been undertaken to better represent urban effects. For this study, the single-layer urban canopy model (SLUCM) of the High-Resolution Land Data Assimilation System (HRLDAS) and WRF Model was used to investigate the sensitivity of near-surface air temperatures and energy fluxes to SLUCM parameters in uncoupled (land) and coupled (land–atmosphere) predictions. Output from HRLDAS and WRF was compared with observations from the Oklahoma Mesonet and Joint Urban 2003 experiment. Variations in roof albedo (0.04–0.4) produced 40–135 W m−2 changes in net radiation and sensible heat fluxes. Sensible and ground heat fluxes varied by 40–100 W m−2 with changes in roof thermal conductivity (0.05–1.4). The urban fraction was found to be the only SLUCM parameter to significantly impact latent heat fluxes. Near-surface air temperatures, particularly during the daytime, did not show significant variations with SLUCM parameters (remaining within the 0.5-K range). Differences in urban air temperatures due to the change in boundary layer scheme were greater than the temperature changes due to SLUCM parameter variations. The sensitivity of near-surface air temperatures to SLUCM parameters depended on the method used to calculate the skin temperature of the impervious surface. For all simulations, predicted 2-m urban air temperatures were consistently higher than observations, with deviations approaching 8 K during the day and below 3 K at night. These large errors affected the model’s skill in reproducing the diurnal cycle of UHI intensity.

scholarly journals Impact of the Climate Matters Program on Public Understanding of Climate Change

2020 ◽  
Vol 12 (4) ◽  
pp. 863-876
Author(s):  
Teresa A. Myers ◽  
Edward W. Maibach ◽  
Bernadette Woods Placky ◽  
Kimberly L. Henry ◽  
Michael D. Slater ◽  
...  
Keyword(s):  
Climate Change ◽  
Political Ideology ◽  
Positive Association ◽  
The United States ◽  
Climatic Conditions ◽  
Public Understanding ◽  
American People ◽  
Significant Positive Association ◽  
The Impact ◽  
Media Market

AbstractClimate Matters is a localized climate change reporting resources program developed to support television (TV) weathercasters across the United States. Developed as a pilot test in one media market in 2010, it launched nationwide in 2013; in the autumn of 2019 more than 797 weathercasters were participating in the program. In this paper we present evidence of the impact of the Climate Matters program on Americans’ science-based understanding of climate change. We analyzed three sets of data in a multilevel model: 20 nationally representative surveys of American adults conducted biannually since 2010 (n = 23 635), data on when and how frequently Climate Matters stories were aired in each U.S. media market, and data describing the demographic, economic, and climatic conditions in each media market. We hypothesized that 1) reporting about climate change by TV weathercasters will increase science-based public understanding of climate change and 2) this effect will be stronger for people who pay more attention to local weather forecasts. Our results partially support the first hypothesis: controlling for market-level factors (population size, temperature, political ideology, and economic prosperity) and individual-level factors (age, education, income, gender, and political ideology), there is a significant positive association between the amount of Climate Matters reporting and some key indicators of science-based understanding (including that climate change is occurring, is primarily human caused, and causes harm). However, there was no evidence for the second hypothesis. These findings suggest that climate reporting by TV weathercasters, as enabled by the Climate Matters program, may be increasing the climate literacy of the American people.

scholarly journals Towards understanding the dynamic behaviour of floodplains as human-water systems

2013 ◽  
Vol 10 (3) ◽  
pp. 3869-3895 ◽  
Author(s):  
G. Di Baldassarre ◽  
M. Kooy ◽  
J. S. Kemerink ◽  
L. Brandimarte
Keyword(s):  
Social Relations ◽  
Flood Control ◽  
Human Impacts ◽  
Water Systems ◽  
Climatic Conditions ◽  
Control Measures ◽  
Hydrological Processes ◽  
Conceptual Approach ◽  
Governance Processes ◽  
The Impact

Abstract. This paper offers a conceptual approach to explore the complex dynamics of floodplains as fully coupled human-water systems. A number of hydrologists have recently investigated the impact of human activities (such as flood control measures, land-use changes, and settlement patterns) on the frequency and severity of floods. Meanwhile, social scientists have shown how interactions between society and waters in floodplain areas, including the frequency and severity of floods, have an impact on the ways in which social relations unfold (in terms of governance processes, policies, and institutions) and societies are organised (spatially, politically, and socially). However, we argue that the interactions and associated feedback mechanisms between hydrological and social processes remain largely unexplored and poorly understood. Thus, there is a need to better understand how the institutions and governance processes interact with hydrological processes in floodplains to influence the frequency and severity of floods, while (in turn) hydrological processes co-constitute the social realm and make a difference for how social relations unfold to shape governance processes and institutions. Our research goal, therefore, is not in identifying one or the other side of the cycle (hydrological or social), but in explaining the relationship between them: how, when, where, and why they interact, and to what result for both social relations and hydrological processes? We argue that long time series of hydrological and social data, along with remote sensing data, can be used to observe floodplain dynamics from unconventional approaches, and understand the complex interactions between water and human systems taking place in floodplain areas, across scales and levels of human impacts, and within different hydro-climatic conditions, socio-cultural settings, and modes of governance.

How is the atmospheric residence time of evapotranspired water altered with a dried-up lake or a forest restoration scenario and what is the impact on precipiation?

2021 ◽  
Author(s):  
Jianhui Wei ◽  
Joël Arnault ◽  
Zhenyu Zhang ◽  
Patrick Laux ◽  
Benjamin Fersch ◽  
...  
Keyword(s):  
Land Use ◽  
Residence Time ◽  
Water Budget ◽  
Forest Restoration ◽  
Water Cycle ◽  
Wrf Model ◽  
Atmospheric Water ◽  
Budget Analysis ◽  
Precipitation Recycling ◽  
The Impact

<p>Land surface characteristics and processes may have complex interactions with the physical and dynamical processes of the atmosphere. However, adequate methods for systemically understanding individual processes of the nonlinearly coupled land-atmosphere continuum are still rare. Therefore, in this study, the age-weighted evaporation tagging approach of Wei et al. (2016) and the three-dimensional online atmospheric water budget analysis of Arnault et al. (2016) were implemented into the Weather Research and Forecast (WRF) model. In addition to the total and tagged atmospheric water states of matter, the latter approach was further extended for age-weighted tagged atmospheric water states of matter, thereby providing a prognostic equation of the residence time of state variables in the atmospheric water cycle.<strong> </strong>This extension allows to systematically quantify the fate of evaporated and transpired water in terms of magnitude, location, composition, and residence time. The extended WRF model was tested for a land use and land cover change study for the Poyang Lake basin, the largest freshwater lake in China. Two hypothetical scenarios, i.e., a dried-up lake and a forest restoration scenario, were simulated and then compared to a real-case control simulation using the original land-use data. The results of the basin-scale precipitation recycling in the context of evapotranspiration partitioning and the modified atmospheric water cycle due to both scenarios will be presented and discussed. We conclude that our newly developed modelling framework and the proposed analysis strategy have the potential to be applied for better understanding and quantifying the nonlinearly intertwined processes between the land and the atmosphere.</p><p>References:</p><p>Arnault, J., Knoche, R., Wei, J., & Kunstmann, H. (2016). Evaporation tagging and atmospheric water budget analysis with WRF: A regional precipitation recycling study for West Africa. Water Resources Research, 52(3), 1544–1567. https://doi.org/10.1002/2015WR017704</p><p>Wei, J., Knoche, R., & Kunstmann, H. (2016). Atmospheric residence times from transpiration and evaporation to precipitation: An age-weighted regional evaporation tagging approach. Journal of Geophysical Research: Atmospheres, 121(12), 6841–6862. https://doi.org/10.1002/2015JD024650</p>

scholarly journals The urban fingerprint in the sea-breeze hodograph reveled by high resolution WRF simulations.

2021 ◽  
Author(s):  
David Avisar ◽  
Ran Pelta ◽  
Alexandra Chudnovsky ◽  
Dorita Rostkier-Edelstein
Keyword(s):  
Wrf Model ◽  
Single Layer ◽  
Urban Canopy ◽  
Sea Breeze ◽  
Building Energy ◽  
Weather Research And Forecasting ◽  
Diurnal Cycles ◽  
Convergence Line ◽  
Urban Heat ◽  
First Time

<p>We implement and verify for the first time four Weather Research and Forecasting (WRF) model urban configurations, focused on the coastal metropolitan area of Tel-Aviv (MTA) using updated land use and urban morphological maps. We analyze the mesoscale summertime flow and the urban canopy (UC) role in the occurrence of different hodograph dynamics observed within MTA at night. These events may be significant in the context of air quality research. The four configurations – bulk (MM), single-layer (SLUCM), multi-layer (BEP), and BEP coupled with the building energy model (BEPBEM) – reproduce the observed diurnal temperature and wind diurnal cycles, with similar 10m wind direction bias and RMSE (15° and ~30°, respectively), with preference for MM and SLUCM at night. However, the SLUCM shows the lowest skill for the 10m wind speed (WS) (bias and RMSE equal or larger than 1ms-1), and the BEP shows the largest underestimation of the 2m temperature, ~-2.5°C. In the SLUCM, the WS increases over an UC region and with increasing building heights. The simulations show that at night, a convergence line (CL) builds up with the urban heat island, downstream of the NW flow. West of the CL, the wind continues flowing from the sea, and rotates anti-clockwise to form a non-elliptical sea-breeze hodograph. Removing MTA UC restores an elliptical hodograph. East of the CL, the UC supports an elliptical hodograph with a clockwise rotation through the NE sector, previously reported as dynamically unstable. We expect such wind hodograph dynamics within similar coastal metropolitan areas.</p>

scholarly journals Towards understanding the dynamic behaviour of floodplains as human-water systems

2013 ◽  
Vol 17 (8) ◽  
pp. 3235-3244 ◽  
Author(s):  
G. Di Baldassarre ◽  
M. Kooy ◽  
J. S. Kemerink ◽  
L. Brandimarte
Keyword(s):  
Social Relations ◽  
Flood Control ◽  
Human Impacts ◽  
Water Systems ◽  
Climatic Conditions ◽  
Control Measures ◽  
Hydrological Processes ◽  
Conceptual Approach ◽  
Governance Processes ◽  
The Impact

Abstract. This paper offers a conceptual approach to explore the complex dynamics of floodplains as fully coupled human-water systems. A number of hydrologists have recently investigated the impact of human activities (such as flood control measures, land-use changes, and settlement patterns) on the frequency and severity of floods. Meanwhile, social scientists have shown how interactions between society and waters in deltas and floodplain areas, including the frequency and severity of floods, have an impact on the ways in which social relations unfold (in terms of governance processes, policies, and institutions) and societies are organised (spatially, politically, and socially). However, we argue that the interactions and associated feedback mechanisms between hydrological and social processes remain largely unexplored and poorly understood. Thus, there is a need to better understand how the institutions and governance processes interact with hydrological processes in deltas and floodplains to influence the frequency and severity of floods, while (in turn) hydrological processes co-constitute the social realm and make a difference for how social relations unfold to shape governance processes and institutions. Our research goal, therefore, is not in identifying one or the other side of the cycle (hydrological or social), but in explaining the relationship between them: how, when, where, and why they interact, and to what result for both social relations and hydrological processes? We argue that long time series of hydrological and social data, along with remote sensing data, can be used to observe floodplain dynamics from unconventional approaches, and understand the complex interactions between water and human systems taking place in floodplain areas, across scales and levels of human impacts, and within different hydro-climatic conditions, socio-cultural settings, and modes of governance.

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