Diurnal Temperature Variability: an Observations-Climate Model Intercomparison
Abstract
Surface temperature measurements since the mid-20thcentury have revealed a diurnally asymmetric global warming trend, with nighttime minimum temperatures increasing faster than daily maxima. The result is an overall decrease in the diurnal temperature range (DTR), which has implications for agriculture, snowpack, human health, as well as the overall magnitude of global warming. There are significant deviations between observed and global climate model (GCM)-simulated baseline DTR over land (generally 1 - 6 ˚C), which raises questions about GCM projections of end-of-century DTR. Here we derived an empirical model using specific humidity to predict DTR, which was used to estimate DTR variability and change given future water vapor concentrations. This empirical model can be used as an emergent property to constrain how the diurnally asymmetric warming may feedback with GHG increases and change with climate change. Significant deviations between observed and GCM-simulated baseline DTR are proposed to be associated with inaccuracies in GCM-simulated water vapor concentrations. This is likely due to limitations in the physical parameterizations of cloud and precipitation processes, warranting further investigation to increase the reliability of global warming projections.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A21H2791R
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3310 Clouds and cloud feedbacks;
- ATMOSPHERIC PROCESSESDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGE