Abstract A two-dimensional version of the Pennsylvania State University mesoscale model has been applied to Winter Monsoon Experiment data in order to simulate the diurnally occurring convection observed over the South China Sea. The domain includes a representation of part of Borneo as well as the sea so that the model can simulate the initiation of convection. Also included in the model are parameterizations of mesoscale ice phase and moisture processes and longwave and shortwave radiation with a diurnal cycle. This allows use of the model to test the relative importance of various heating mechanisms to the stratiform cloud deck, which typically occupies several hundred kilometers of the domain. Frank and Cohen's cumulus parameterization scheme is employed to represent vital unresolved vertical transports in the convective area. The major conclusions are: Ice phase processes are important in determining the level of maximum large-scale heating and vertical motion because there is a strong anvil componen...

Numerical study of convection observed during the Winter Monsoon Experiment using a mesoscale two-dimensional model [presentation]

Recent progress on urban overheating and heat island research. integrated assessment of the energy, environmental, vulnerability and health impact synergies with the global climate change

The focus of this study is an intense heat episode that occurred on 9–13 July 2017 in Beijing, China, that resulted in severe impacts on natural and human variables, including record-settin...

An Observational Case Study of Synergies between an Intense Heat Wave and the Urban Heat Island in Beijing

The Urban Heat Island (UHI) phenomenon is frequently associated with heat waves, both in scientific literature and in the media. Health problems and other issues often result from the co-occurrence of these two phenomena. Previous studies have not yet provided sufficient evidence to validate potential links between UHIs and heat waves. The MUSTARDijon network was set up in 2014, in Dijon, France. Its spatial density (60 sensors) and temporal depth (6 summers) provide information about several Hot Spells and Heat Waves (HSH these two conditions are frequently met during HS&HW, but not systematically. By contrast, these conditions can be fulfilled even without high temperatures. Strong UHIs can thus develop outside Hot Spell/Heat Wave (HS/HW) events. These HS&HW are not necessarily in phase with UHIs: maximum UHI intensity tends to occur before the onset or during the first few days of HS&HW. The intensity of the UHI decreases during HS&HW because nocturnal urban temperature generally remains stationary, whereas rural temperature tends to increase at night. The hypothesis proposed is that this increase in rural night temperature during HS&HW could be linked to the decrease in Actual Evapotranspiration (ETa) and soil wetness.

Is Urban Heat Island intensity higher during hot spells and heat waves (Dijon, France, 2014-2019)?

Buildings and the atmosphere are intrinsically connected via cooling and heating systems. Global climate is projected to grow warmer, with an increasing fraction of the population living in urban centers. This introduces the challenge for new approaches to project future energy demand changes in cities. In New York City (NYC), the focus of our study, while air conditioning only accounts for 9% of all building energy end use, it is the main driver of annual peak electric demand. Here, we present end of century building cooling electric demand projections for NYC using a high resolution (1 km) configuration of the Weather Research and Forecasting model coupled to a building energy model and forced by bias-corrected CESM1 global simulations. High resolution urban canopy parameters such as building height and plant area fraction derived from a public tax-lot level dataset are used as input to the urban physics parameterization. Cooling demand increases in RCP4.5 ranged between 1% and 20% across all days, with largest increases on days below 50th percentile demand. Results show that end of century building cooling demand on days below the 50th percentile may be up to 80% higher than the 2006–2010 period in the RCP8.5 scenario. The largest percent increases per unit area were found over less densely populated boroughs of Brooklyn, Queens, and Staten Island. Maximum summer cooling demand for the entire city is projected to increase between 5% and 27% for RCP4.5 and RCP8.5, respectively. Overall, analysis shows a close to 8% increase in cooling demand per 1 °C increase in temperature.

https://iopscience.iop.org/article/10.1088/1748-9326/aad8d0/pdf

Climate change impacts on peak building cooling energy demand in a coastal megacity

Heat waves are projected to increase in magnitude and frequency throughout this century because of increasing global temperatures, making it critically important to acquire improved understanding of their genesis and interactions with large cities This study presents an application of the method of factor separation to assess combined impacts of a synoptic-scale heat wave, urban land cover, and urban energy and momentum fluxes on temperatures and winds over New York City, New York, via use of high-resolution simulations (1-km grid spacing) with an urbanized version of the Weather Research and Forecasting (WRF) Model Results showed that factors behaved different throughout the day, with synoptic conditions dominating afternoon temperature contributions (>7°C) At night, combined urban surface factors contributed over 5°C during the heat wave and up to 15°C on non-heat-wave days Positive interactions among all factors during morning and nighttime indicate an amplification of the urban heat islan

Jeffrey Tongue

Papers

New York City Impacts on a Regional Heat Wave