Identification

Title

Tropical cyclone intensity errors associated with lack of two-way ocean coupling in high-resolution global simulations

Abstract

Tropical cyclones (TCs), particularly those that are intense and/or slow moving, induce sea surface temperature (SST) reductions along their tracks (commonly referred to as cold wakes) that provide a negative feedback on storm energetics by weakening surface enthalpy fluxes. While computing gains have allowed for simulated TC intensity to increase in global climate models as a result of increased horizontal resolution, many configurations utilize prescribed, noninteractive SSTs as a surface boundary condition to minimize computational cost and produce more accurate TC climatologies. Here, an idealized slab ocean is coupled to a 0.25 degrees variable-resolution version of the Community Atmosphere Model (CAM) to improve closure of the surface energy balance and reproduce observed Northern Hemisphere cold wakes. This technique produces cold wakes that are realistic in structure and evolution and with magnitudes similar to published observations, without impacting large-scale SST climatology. Multimember ensembles show that the overall number of TCs generated by the model is reduced by 5%-9% when allowing for two-way air-sea interactions. TC intensity is greatly impacted; the strongest 1% of all TCs are 20-30 hPa (4-8 m s(-1)) weaker, and the number of simulated Saffir-Simpson category 4 and 5 TCs is reduced by 65% in slab ocean configurations. Reductions in intensity are in line with published thermodynamic theory. Additional offline experiments and sensitivity simulations demonstrate this response is both significant and robust. These results imply caution should be exercised when assessing high-resolution prescribed SST climate simulations capable of resolving intense TCs, particularly if discrete analysis of extreme events is desired.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d73x88fj

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

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Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2016-12-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

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name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact