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Pu Z.,University of Utah | Zhang L.,University of Utah | Emmitt G.D.,Simpson Weather Associates, Inc.
Geophysical Research Letters | Year: 2010

During the THORPEX Pacific Asian Regional Campaign (TPARC) field experiment in 2008, an airborne Doppler wind lidar (DWL) was onboard the U.S. Naval Research Laboratory's P-3 research flight. It was the first time the DWL was used for a tropical cyclone mission. This paper presents the first results demonstrating the impact of airborne DWL measurements on the numerical simulation of Typhoon Nuri (2008) in its formation phase. With an advanced research version of the weather research and forecasting (WRF) model and its data assimilation systems, numerical results show the DWL data have a positive impact on numerical simulations of Typhoon Nuri in terms of its formation, track and intensity. Dropsondes released in the areas where the DWL was operating show good agreement for measured winds. Compared with the three-dimensional variational method, a four-dimensional variational data assimilation system is deemed to be more promising for assimilating the DWL data. Copyright © 2010 by the American Geophysical Union. Source

Emmitt G.D.,Simpson Weather Associates, Inc.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2010

The first ever extensive study of tropical cyclones using Doppler Wind Lidars (DWL) was conducted in 2008 within the THORPEX Pacific Asian Regional Campaign. More than 100 hours of DWL profiles were obtained with an average spacing of 3km. These wind profiles along with dropsonde temperature, moisture and wind profiles are being used to study the genesis and evolution of tropical cyclones. Initial investigations are focused upon the impact the DWL profiles have on numerical weather prediction. © 2010 IEEE. Source

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 111.37K | Year: 2005

The primary Phase I technical objective is to demonstrate the feasibility of converting an existing set of functional code meant for post-flight processing and visualization of airborne DWL data into a form that better meets the timeliness and data volume requirements associated with on-board data processing and data transmission for use by the Army's IMETS models and tactical decision aides. These real-time wind and aerosol data represent a major new input to the support network for the US Army's Objective Force. During Phase I we will conduct a proof-of- concept demonstration of a software package (ADLAATS: Airborne Doppler Lidar Analyses and Adaptive Targeting System) that will process raw DWL data in real-time (onboard aircraft) and provide derived products (wind components, aerosol backscatter and the variability of both the winds and aerosols) that can be displayed and/or transmitted to a ground station in a timely fashion. Additional information on the depth of the PBL, identification of anomalies in aerosol backscatter or winds, enabled adaptive selection of scan patterns and enabled adaptive space/time data averaging will be included. We will also develop plans for Phase II field tests of ADLAATS and numerical model impact evaluations.

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 445.49K | Year: 2007

During Phase I, we determined the feasibility of an In-flight Lidar Integrated Mission Management System (I-LIMMS) and developed both a preliminary design and architecture for the entire system. This included defining a data test bed and determining all hardware, software and visualization requirements. During the Phase II effort, we will fully develop and code an I-LIMMS that will provide real time 4-D visualization of both lidar and in-situ data, as well as provide on-board guidance for in-flight decision making. More specifically, we will: create or modify all software to optimize the in-flight processing and collection of the lidar and in-situ data; design, code and develop the integrated graphics software that will provide the real time 4-D visualization of lidar and in-situ measurements; fully populate a preliminary “mode library” that will be used for in-flight mission management; and develop the software architecture to connect and communicate with all hardware, graphics and interfaces aboard the aircraft. All activities during this Phase II effort will be focused on preparing I-LIMMS for integration and testing aboard the CIRPAS Twin Otter aircraft. It is anticipated that this testing and integration will take place near the end of the Phase II effort.

De Wekker S.F.J.,University of Virginia | Godwin K.S.,University of Virginia | Emmitt G.D.,Simpson Weather Associates, Inc. | Greco S.,Simpson Weather Associates, Inc.
Journal of Applied Meteorology and Climatology | Year: 2012

Three-dimensional winds obtained with an airborne Doppler lidar are used to investigate the spatial structure of topographically driven flows in complex coastal terrain in Southern California. The airborne Doppler lidar collected four hours of data between the surface and 3000 mMSL along a 40-km segment of the Salinas Valley during the afternoon of 12 November 2007. The airborne lidar measurements, obtained at horizontal and vertical resolutions of approximately 1500 and 50 m, respectively, reveal a detailed spatial structure of the atmospheric flows within the valley and their associated aerosol features. Clear skies prevailed on the flight day with northwesterly synoptic flows around 10 m s21. The data document a shallow sea breeze making a transition into an upvalley flow in the Salinas Valley that accelerates in the upvalley direction. Along with the acceleration of the upvalley wind, the lidar data indicate the presence of enhanced sinking motions. No return flows associated with the sea-breeze or upvalley flows are observed. While synoptic flows are aligned along the valley axis in the upvalley direction, lidar data indicate the presence of a northerly crossvalley flow around the height of the surrounding ridges. This flow intrudes into the valley atmosphere and induces, along with thermally driven slope flows on the sunlit valley sidewall, a cross-valley circulation that causes an asymmetric distribution of the aerosols. This study demonstrates the large potential of airborne Doppler lidar data in describing flows in complex terrain. © 2012 American Meteorological Society. Source

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