Tropical Free-Tropospheric Humidity Differences and Their Effect on the Clear-Sky Radiation Budget in Global Storm-Resolving Models

Link:
Autor/in:
Erscheinungsjahr:
2021
Medientyp:
Text
Schlagworte:
  • free troposphere
  • humidity
  • outgoing longwave radiation
  • storm-resolving models
  • Atmospheric boundary layer
  • Atmospheric humidity
  • Budget control
  • Climate models
  • Earth system models
  • Storms
  • Subsidence
  • Troposphere
  • Clear sky
  • Free troposphere
  • Model Differences
  • Outgoing longwave radiation
  • Radiation budget
  • Sky radiation
  • Storm-resolving model
  • Tropospheric humidity
  • Uncertainty
  • Upper troposphere
  • Tropics
  • longwave radiation
  • moisture
  • region
  • space
  • tropopause
  • warming
Beschreibung:
  • Reducing the model spread in free-tropospheric relative humidity (RH) and its response to warming is a crucial step toward reducing the uncertainty in clear-sky climate sensitivity, a step that is hoped to be taken with recently developed global storm-resolving models (GSRMs). In this study we quantify the inter-model differences in tropical present-day RH across GSRMs, making use of DYAMOND, a first 40-day intercomparison. We find that the inter-model spread in tropical mean free-tropospheric RH is reduced compared to conventional atmospheric models, except from the tropopause region and the transition to the boundary layer. We estimate the reduction to ∼50%–70% in the upper troposphere and 25%–50% in the mid troposphere. However, the remaining RH differences still result in a spread of 1.2 (Formula presented.) in tropical mean clear-sky outgoing longwave radiation (OLR). This spread is mainly caused by RH differences in the lower and mid free troposphere, whereas RH differences in the upper troposphere have a minor impact. By examining model differences in moisture space we identify two regimes with a particularly large contribution to the spread in tropical mean clear-sky OLR: rather moist regimes at the transition from deep convective to subsidence regimes and very dry subsidence regimes. Particularly for these regimes a better understanding of the processes controlling the RH biases is needed. © 2021 The Authors. Journal of Advances in Modeling Earth Systems published by Wiley Periodicals LLC on behalf of American Geophysical Union.
Lizenz:
  • info:eu-repo/semantics/openAccess
Quellsystem:
Forschungsinformationssystem der UHH
Interne Metadaten
Quelldatensatz
oai:www.edit.fis.uni-hamburg.de:publications/a351d665-13d6-46ca-81bc-13d0832e5de0