A case study of turbulence in the nocturnal boundary layer during the Indian summer monsoon

Deb Burman, Pramit Kumar; Prabha, Thara V.; Morrison, Ross ORCID: https://orcid.org/0000-0002-1847-3127; Karipot, Anandakumar. 2018 A case study of turbulence in the nocturnal boundary layer during the Indian summer monsoon. Boundary-Layer Meteorology, 169 (1). 115-138. https://doi.org/10.1007/s10546-018-0364-4

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Official URL: https://doi.org/10.1007/s10546-018-0364-4

Abstract/Summary

Observations from the Cloud-Aerosol Interaction and Precipitation Enhancement Experiment-Integrated Ground Observation Campaign (CAIPEEX-IGOC) provide a rare opportunity to investigate nocturnal atmospheric surface-layer processes and surface-layer turbulent characteristics associated with the low-level jet (LLJ). Here, an observational case study of the nocturnal boundary layer is presented during the peak monsoon season over Peninsular India using data collected over a single night representative of the synoptic conditions of the Indian summer monsoon. Datasets based on Doppler lidar and eddy-covariance are used for this purpose. The LLJ is found to generate nocturnal turbulence by introducing mechanical shear at higher levels within the boundary layer. Sporadic and intermittent turbulent events observed during this period are closely associated with large eddies at the scale of the height of the jet nose. Flux densities in the stable boundary layer are observed to become non-local under the influence of the LLJ. Different turbulence regimes are identified, along with transitions between turbulent periods and intermittency. Wavelet analysis is used to elucidate the presence of large-scale eddies and associated intermittency during nocturnal periods in the surface layer. Although the LLJ is a regional-scale phenomenon it has far reaching consequences with regard to surface-atmosphere exchange processes.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1007/s10546-018-0364-4
UKCEH and CEH Sections/Science Areas:	Hydro-climate Risks (Science Area 2017-)
ISSN:	0006-8314
Additional Information. Not used in RCUK Gateway to Research.:	Publisher link (see Related URLs) provides a read-only full-text copy of the published paper.
Additional Keywords:	cospectral analysis, intermittency, low-level jet, nocturnal boundary layer, wavelet analysis
NORA Subject Terms:	Atmospheric Sciences
Related URLs:	Publisher
Date made live:	20 Jun 2018 09:11 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/520337

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1007/s10546-018-0364-4

UKCEH and CEH Sections/Science Areas:

Hydro-climate Risks (Science Area 2017-)

ISSN:

0006-8314

Additional Information. Not used in RCUK Gateway to Research.:

Publisher link (see Related URLs) provides a read-only full-text copy of the published paper.

Additional Keywords:

cospectral analysis, intermittency, low-level jet, nocturnal boundary layer, wavelet analysis