Identification

Title

Multiscale characteristics of an extreme precipitation event over Nepal

Abstract

This study focuses on the analysis of the extreme precipitation event in Central Nepal on 19 July 2007 which was part of a sequence of rain events leading to the devastating South Asia flood of 2007. We investigate synoptic-scale conditions using reanalyses and attribute moisture sources with a Lagrangian moisture source diagnostic. Further, we characterize the mesoscale precipitation event with a high-resolution numerical simulation. The simulation reveals an intense wide convective event with a simulated 40 dBZ echo core of considerable horizontal extent (1,550 km(2)) exceeding a height of 12 km. Initially small convective cells were invigorated by high CAPE and a potentially unstable layer at mid-tropospheric levels. This layer reached conditional instability adding latent energy to the system. Isolated convective cells organized upscale into a wide intense convective system, fuelled with moist low-level inflow. The result was torrential rain with over 250 mm within 24 hr. Several synoptic-scale conditions contributed to the intense development: (a) supply of moist air with the help of a typical monsoon break condition flow pattern, (b) anomalously significant moisture sources along this path due to prior precipitation events, (c) an upper-tropospheric trough orienting the atmospheric flow against the Himalayas with associated quasi-geostrophic forcing creating a favourable environment for convection, and (d) destabilized stratification due to an upslope flow. This analysis encompasses multiple scales and shows how a wide intense convective system, not unusual for this region, can be intensified by distinct synoptic constituents.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7rj4nhk

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

2018-12-26T00:00:00Z

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