Identification

Title

The impacts of Taiwan topography on the predictability of Typhoon Morakot's record-breaking rainfall: A high-resolution ensemble simulation

Abstract

In this study, we examine the impact of Taiwan topography on the extreme rainfall of Typhoon Morakot and the predictability of this rainfall with a high-resolution (4-km) ensemble simulation using the Advanced Research WRF (ARW) model. Ensemble prediction with realistic topography reproduces salient features of orographic precipitation. The 24-h and 96-h accumulated rainfall amount and distribution from the ensemble mean compares reasonably well with the observed precipitation. When the terrain of Taiwan is removed, the rainfall distribution is markedly changed suggesting the importance of the orography in determining the rainfall structure. Moreover, the peak 96-h rainfall amount is reduced to less than 20%, and the total rainfall amount over southern Taiwan is reduced to less than 60% of the experiments with Taiwan topography. Further analysis indicates that Taiwan's topography substantially increases the variability of rainfall prediction. Analysis uncertainties as reflected in the perturbed initial state of the ensemble are amplified due to orographic influences on the typhoon circulation. As a result, significant variability occurs in storm track, timing and location of landfall, and storm intensities, which in turn, increases rainfall variability. These results suggest that accurate prediction of heavy precipitation at a specific location and at high temporal resolution for an event such as Typhoon Morakot over Taiwan is extremely challenging. The forecasting of such event would benefit from probabilistic prediction provided by a high-resolution mesoscale ensemble forecast system.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d72n53k2

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

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2011-10-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

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