Interaction Between the Aerosol Direct Effect in the Lower Troposphere and the Planetary Boundary Layer

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dc.contributor.advisorLi, Zhanqingen_US
dc.contributor.authorSawyer, Virginia Ruthen_US
dc.contributor.departmentAtmospheric and Oceanic Sciencesen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2016-02-06T06:33:17Z
dc.date.available2016-02-06T06:33:17Z
dc.date.issued2015en_US
dc.description.abstractThe planetary boundary layer (PBL) limits the vertical mixing of aerosol emitted to the lower troposphere. The PBL depth and its change over time affect weather, surface air quality and radiative forcing. While model simulations have suggested that the column optical properties of aerosol are associated with changes in the PBL depth in turn, there are few long-term measurements of PBL depth with which to validate the theory. Of the existing methods to detect the PBL depth from atmospheric profiles, many require supporting information from multiple instruments or cannot adapt to changing atmospheric conditions. This study combines two common methods for PBL depth detection (wavelet covariance and iterative curve-fitting) in order to produce more reliable PBL depths for micropulse lidar backscatter (MPL). The combined algorithm is also flexible enough to use with radiosonde and atmospheric emitted radiance interferometer (AERI) data. PBL depth retrievals from these three instruments collected at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site are compared to one another to show the robustness of the algorithm. The comparisons were made for different times of day, four seasons, and variable sky conditions. While considerable uncertainties exist in PBL detection using all three types of measurements, the agreement among the PBL products is promising, and the different measurements have complementary advantages. The best agreement in the seasonal cycle occurs in winter, and the best agreement in the diurnal cycle when the boundary-layer regime is mature and changes slowly. PBL depths from instruments with higher temporal resolution (MPL and AERI) are of comparable accuracy to radiosonde-derived PBL depths. The new PBL depth measurements for SGP are compared to MPL-derived PBL depths from a multiyear lidar deployment at the Hefei Radiation Observatory (HeRO), and the column aerosol optical depth (AOD) for each site is considered. A one-month period at SGP is also modeled to relate AOD to PBL depth. These comparisons show a weak inverse relationship between AOD and daytime PBL depth. This is consistent with predictions that aerosol suppresses surface convection and causes shallower PBLs.en_US
dc.identifierhttps://doi.org/10.13016/M2542B
dc.identifier.urihttp://hdl.handle.net/1903/17221
dc.language.isoenen_US
dc.subject.pqcontrolledAtmospheric chemistryen_US
dc.subject.pqcontrolledAtmospheric sciencesen_US
dc.subject.pquncontrolledaerosolen_US
dc.subject.pquncontrolledaerosol direct effecten_US
dc.subject.pquncontrolledaerosol optical depthen_US
dc.subject.pquncontrolledlidaren_US
dc.subject.pquncontrolledplanetary boundary layeren_US
dc.subject.pquncontrolledradiosondeen_US
dc.titleInteraction Between the Aerosol Direct Effect in the Lower Troposphere and the Planetary Boundary Layeren_US
dc.typeDissertationen_US

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