The vertical profi le of recent tropical temperature trends: Persistent model biases in the context of internal variability

Autor(en)

Dann M. Mitchell, Y. T. Eunice Lo, William J. M. Seviour, Leopold Haimberger, Lorenzo M. Polvani

Abstrakt

Tropospheric and stratospheric tropical temperature trends in recent decades have been notoriously hard to simulate using climate models, particularly in the upper troposphere. Aside from the warming trend itself, this has broader implications, e.g. atmospheric circulation trends depend on latitudinal temperature gradients. In this study, tropical temperature trends in the CMIP6 models are examined, from 1979 to 2014, and contrasted with trends from the RICH/RAOBCORE radiosondes, and the ERA5/5.1 reanalysis. As in earlier studies, we find considerable warming biases in the CMIP6 modeled trends, and we show that these biases are linked to biases in surface temperature. We also uncover previously undocumented biases in the lower-middle stratosphere: the CMIP6 models appear unable to capture the time evolution of stratospheric cooling, which is non-monotonic owing to the Montreal Protocol. Finally, using models with large ensembles, we show that their standard deviation in tropospheric temperature trends, which is due to internal variability alone, explains ∼ 50% (± 20%) of that from the CMIP6 models.

Organisation(en)

Institut für Meteorologie und Geophysik

Externe Organisation(en)

University of Bristol, Columbia University in the City of New York

Journal

Environmental Research Letters

Band

15

Anzahl der Seiten

11

ISSN

1748-9326

DOI

https://doi.org/10.1088/1748-9326/ab9af7

Publikationsdatum

10-2020

Peer-reviewed

Ja

ÖFOS 2012

105206 Meteorologie

Schlagwörter

ASJC Scopus Sachgebiete

Public Health, Environmental and Occupational Health, Environmental Science(all), Renewable Energy, Sustainability and the Environment

Sustainable Development Goals

SDG 13 – Maßnahmen zum Klimaschutz

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/the-vertical-profi-le-of-recent-tropical-temperature-trends-persistent-model-biases-in-the-context-of-internal-variability(a441db60-cd3d-4a87-b631-a39a166a6fab).html