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Scale interactions near the foothills of Himalayas during CAIPEEX

Prabha, TV and Karipot, A and Axisa, D and Kumari, BP and Maheskumar, RS and Konwar, M and Kulkarni, JR and Goswami, BN (2012) Scale interactions near the foothills of Himalayas during CAIPEEX. Journal of Geophysical Research D: Atmospheres, 117 (10).

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Scale interactions associated with small scale (<100 km) dynamics might play a crucial role in the distribution of aerosol in the Himalayan foothills region. Turbulence measurements from a horizontal flight path during Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) are used to illustrate the scale interactions in the vertically sheared flow below the high-level subtropical westerly jet, which is important in the transport of pollution. Data analysis reveals the three dimensional property of large eddies that scale 10-12 km near the slopes, which could bring pollution from the valley to the Tibetan Plateau through a circulation adhering to the slopes. This circulation has a subsidence region away from the slopes and may also contribute to the buildup of pollution in elevated layers over the Plains. The vertical velocity and temperature spectra from research flight data showed clear indications of (-5/3) slope in the mesoscale range. The isotropic behavior of the velocity spectra was noticed for cloud-free traverses, while this behavior is distorted for cloudy conditions with the enhancement of energy at smaller scales as well as with low frequency gravity wave generation. A high-resolution cloud allowing model simulation over the flight path is used to examine the representation of these dynamical interactions in the numerical model. Based on the analysis of observational data and model inferences, a conceptual understanding of the flow in the region close to the foot hills and its role in the distribution of aerosol and cloud condensation nuclei is presented.

Item Type: Article
Additional Information: Copyright of this article belongs to American Geophysical Union.
Uncontrolled Keywords: Cloud condensation nuclei; Cloudy conditions; Conceptual understanding; Dimensional properties; Dynamical interactions; Flight data; High resolution; Himalayas; Isotropic behaviors; Large eddy; Low frequency; Mesoscale; Model inference; Model simulation; Observational data; Precipitation enhancement; Scale interactions; Sheared flow; Small scale; Temperature spectra; Tibetan Plateau; Turbulence measurements; Velocity spectrum; Vertical velocity; Wave generation, Atmospheric aerosols; Data flow analysis; Flight paths; Pollution; Precipitation (meteorology), Atmospheric movements, aerosol property; atmospheric pollution; cloud condensation nucleus; data interpretation; data set; eddy; isotropy; jet stream; mountain region; numerical model; pollutant transport; scale effect; spatial distribution; subsidence; turbulence; westerly, China; Himalayas; Qinghai-Xizang Plateau
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 27 Dec 2013 20:45
Last Modified: 27 Dec 2013 20:45

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