Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings

Climate extremes affected cities and their populations during the last decades. Future climate projections indicate climate extremes will increasingly impact urban areas during the 21st century. Humidity related fluctuations and extremes directly underpin convective processes, as well as can influen...

Full description

Bibliographic Details
Main Authors: G.S. Langendijk, D. Rechid, K. Sieck, D. Jacob
Format: Article
Language:English
Published: Elsevier 2021-09-01
Series:Weather and Climate Extremes
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2212094721000578
_version_ 1818572766220124160
author G.S. Langendijk
D. Rechid
K. Sieck
D. Jacob
author_facet G.S. Langendijk
D. Rechid
K. Sieck
D. Jacob
author_sort G.S. Langendijk
collection DOAJ
description Climate extremes affected cities and their populations during the last decades. Future climate projections indicate climate extremes will increasingly impact urban areas during the 21st century. Humidity related fluctuations and extremes directly underpin convective processes, as well as can influence human health conditions. Regional climate models are a powerful tool to understand regional-to-local climate change processes for cities and their surroundings. Convection-permitting regional climate models, operating on very high resolutions, indicate improved simulation of convective extremes, particularly on sub-daily timescales and in regions with complex terrain such as cities. This research aims to understand how crossing spatial resolutions from ~12.5 km to ~3 km grid size affect humidity extremes and related variables under future climate change for urban areas and its surroundings. Taking Berlin and its surroundings as the case study area, the research identifies two categories of unprecedented future extreme atmospheric humidity conditions happening under 1.5 °C and 2.0 °C mean warming based on statistical distributions, respectively near surface specific humidity >0.02 kg/kg and near surface relative humidity <30%. Two example cases for each future extreme condition are dynamically downscaled for a two months period from the 0.44° horizontal resolution following a double-nesting approach: first to the 0.11° (~12.5 km) horizontal resolution with the regional climate model REMO and thereafter to the 0.0275° (~3 km) horizontal resolution with the non-hydrostatic version of REMO. The findings show that crossing spatial resolutions from ~12.5 km to ~3 km grid size affects humidity extremes and related variables under climate change. Generally, a stronger decrease in moisture (up to 0.0007–0.005 kg/kg SH and 10–20% RH) and an increase in temperature (1–2 °C) is found on the 0.0275° compared to the 0.11° horizontal resolution, which is more profound in Berlin than in the surroundings. The convection-permitting scale mitigates the specific humidity moist extreme and intensifies the relative humidity dry extreme in Berlin, posing challenges with respect to health for urban dwellers.
first_indexed 2024-12-15T00:02:02Z
format Article
id doaj.art-a8bc823b29484d74828e5254b81c578b
institution Directory Open Access Journal
issn 2212-0947
language English
last_indexed 2024-12-15T00:02:02Z
publishDate 2021-09-01
publisher Elsevier
record_format Article
series Weather and Climate Extremes
spelling doaj.art-a8bc823b29484d74828e5254b81c578b2022-12-21T22:42:52ZengElsevierWeather and Climate Extremes2212-09472021-09-0133100367Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundingsG.S. Langendijk0D. Rechid1K. Sieck2D. Jacob3Climate Service Center Germany (GERICS), Helmholtz-Zentrum Hereon, Fischertwiete 1, 20095 Hamburg, Germany; Faculty of Sustainability, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany; Corresponding author. Climate Service Center Germany (GERICS), Helmholtz-Zentrum Hereon, Fischertwiete 1, 20095 Hamburg, Germany.Climate Service Center Germany (GERICS), Helmholtz-Zentrum Hereon, Fischertwiete 1, 20095 Hamburg, GermanyClimate Service Center Germany (GERICS), Helmholtz-Zentrum Hereon, Fischertwiete 1, 20095 Hamburg, GermanyClimate Service Center Germany (GERICS), Helmholtz-Zentrum Hereon, Fischertwiete 1, 20095 Hamburg, Germany; Faculty of Sustainability, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, GermanyClimate extremes affected cities and their populations during the last decades. Future climate projections indicate climate extremes will increasingly impact urban areas during the 21st century. Humidity related fluctuations and extremes directly underpin convective processes, as well as can influence human health conditions. Regional climate models are a powerful tool to understand regional-to-local climate change processes for cities and their surroundings. Convection-permitting regional climate models, operating on very high resolutions, indicate improved simulation of convective extremes, particularly on sub-daily timescales and in regions with complex terrain such as cities. This research aims to understand how crossing spatial resolutions from ~12.5 km to ~3 km grid size affect humidity extremes and related variables under future climate change for urban areas and its surroundings. Taking Berlin and its surroundings as the case study area, the research identifies two categories of unprecedented future extreme atmospheric humidity conditions happening under 1.5 °C and 2.0 °C mean warming based on statistical distributions, respectively near surface specific humidity >0.02 kg/kg and near surface relative humidity <30%. Two example cases for each future extreme condition are dynamically downscaled for a two months period from the 0.44° horizontal resolution following a double-nesting approach: first to the 0.11° (~12.5 km) horizontal resolution with the regional climate model REMO and thereafter to the 0.0275° (~3 km) horizontal resolution with the non-hydrostatic version of REMO. The findings show that crossing spatial resolutions from ~12.5 km to ~3 km grid size affects humidity extremes and related variables under climate change. Generally, a stronger decrease in moisture (up to 0.0007–0.005 kg/kg SH and 10–20% RH) and an increase in temperature (1–2 °C) is found on the 0.0275° compared to the 0.11° horizontal resolution, which is more profound in Berlin than in the surroundings. The convection-permitting scale mitigates the specific humidity moist extreme and intensifies the relative humidity dry extreme in Berlin, posing challenges with respect to health for urban dwellers.http://www.sciencedirect.com/science/article/pii/S2212094721000578Urban-rural contrastsHumidityFuture climate extremesRegional climate modellingConvection permitting
spellingShingle G.S. Langendijk
D. Rechid
K. Sieck
D. Jacob
Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings
Weather and Climate Extremes
Urban-rural contrasts
Humidity
Future climate extremes
Regional climate modelling
Convection permitting
title Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings
title_full Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings
title_fullStr Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings
title_full_unstemmed Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings
title_short Added value of convection-permitting simulations for understanding future urban humidity extremes: case studies for Berlin and its surroundings
title_sort added value of convection permitting simulations for understanding future urban humidity extremes case studies for berlin and its surroundings
topic Urban-rural contrasts
Humidity
Future climate extremes
Regional climate modelling
Convection permitting
url http://www.sciencedirect.com/science/article/pii/S2212094721000578
work_keys_str_mv AT gslangendijk addedvalueofconvectionpermittingsimulationsforunderstandingfutureurbanhumidityextremescasestudiesforberlinanditssurroundings
AT drechid addedvalueofconvectionpermittingsimulationsforunderstandingfutureurbanhumidityextremescasestudiesforberlinanditssurroundings
AT ksieck addedvalueofconvectionpermittingsimulationsforunderstandingfutureurbanhumidityextremescasestudiesforberlinanditssurroundings
AT djacob addedvalueofconvectionpermittingsimulationsforunderstandingfutureurbanhumidityextremescasestudiesforberlinanditssurroundings