From: Don Lenschow (lenschow at ucar.edu)
Organization: NCAR

Research Area: OTHER

Mission Scenario: Surface-Atmosphere Interactions

The Earth's surface is the main source or sink for most climatologically important trace atmospheric constituents. The planetary boundary layer (PBL) is the conduit through which these constituents must pass on their way to and from the surface. The mechanism for transport is turbulence, which is a distinguishing characteristic of the PBL. Therefore, measuring transport of trace species through the PBL provides a means for estimating sources and sinks of these species, and relate them to e.g. season, time-of-day, weather, geographic location, fertility, and soil conditions. The HIAPER provides a platform for carrying out such studies in remote areas inaccessible to small aircraft, and difficult to reach on the ground, as well as rapid deployment to sites where a complement of collaborative ground-based observations are being conducted.

HIAPER mission: Fly to remote locations at different times of the year to measure trace constituent fluxes, along with supporting observations of mean thermodynamic and dynamic variables of the lower troposphere. Examples of fluxes include: latent and sensible heat, momentum, carbon dioxide, ozone, dimethyl sulfide, and aerosols. Flight patterns would generally consist of a combination of long transects at one or two levels to obtain surface fluxes over a region of at least several hundred kilometers in extent, a series of flight legs at several levels over the same region to obtain flux profiles throught the PBL, and repeated flight legs over the same path to obtain good averaged statistics and measure the variability of the fluxes.

An extension of this basic strategy would be to use remote sensing to obtain measurements of e.g. water vapor flux profiles throughout the PBL. This would involve concurrent downward-looking water vapor DIAL and Doppler lidar measurements of water vapor and vertical velocity. A conically scanning Doppler lidar might be able to also measure vertical momentum flux. This would greatly expand the geographic coverage of flux measurements.

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