Atmospheric-boundary-layer height retrieval using microwave radiometer and lidar sensors : algorithms and error estimation
The Atmospheric Boundary Layer Height (ABLH) is an important parameter in weather forecasting, meteorology, avionics, and air-quality and dispersion models. Local development of the Atmospheric Boundary Layer (ABL) over the full diurnal cycle is a function of several parameters which, among others,...
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| Formato: | tesis doctoral |
| Fecha de publicación: | 2016 |
| País: | España |
| Recursos: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/96399 |
| Acesso em linha: | https://hdl.handle.net/2117/96399 https://dx.doi.org/10.5821/dissertation-2117-96399 |
| Access Level: | acceso abierto |
| Palavra-chave: | Radiació -- Mesurament Kalman, Filtratge de Fotònica Àrees temàtiques de la UPC::Enginyeria de la telecomunicació |
| Resumo: | The Atmospheric Boundary Layer Height (ABLH) is an important parameter in weather forecasting, meteorology, avionics, and air-quality and dispersion models. Local development of the Atmospheric Boundary Layer (ABL) over the full diurnal cycle is a function of several parameters which, among others, include geographical location of the place, its topography, time of the year, and day and night conditions. There are several remote sensing instruments and methods to retrieve the ABLH, however, none of these can fully measure ABL development under all atmospheric conditions. This Ph.D. thesis deals with estimation of the ABLH over the full diurnal cycle, which includes day-time mixing layer, nocturnal stable boundary layer, and morning/evening transition boundary layer, by using ground-based microwave-radiometer (MWR) and ceilometer (lidar principle) remote-sensing instruments as well as related signal processing techniques. ABLH estimates from Doppler lidar and radiosondes are used as references. Aim of this thesis is also to combine data from these two instruments, thus, exploiting their individual strengths and overcoming their limitations. In this context, this thesis has been structured around three main goals: First, a synergetic method for estimation of the Mixing Layer Height (MLH) is presented. Towards this end, uncertainties in the MLH derived from backscattered ceilometer signals and MWR-retrieved potential temperature profiles are analysed and compared. While the Extended Kalman Filter (EKF) is used as adaptive filter to process backscattered lidar signals from the ceilometer, the parcel method is used with the MWR-retrieved potential temperature profile. Finally, the two methods are combined into a new methodology for synergetic MLH retrieval. Second, methods for the estimation of the nocturnal Stable-Boundary-Layer Height (SBLH) from ceilometer and MWR data, in stand-alone and in synergetic fashion, are investigated. The SBLH from ceilometer backscattered lidar signals is retrieved by using Minimum Variance Regions (MVRs) as signatures of aerosol stratification in the SBL. For the MWR, idealized physical models from the literature are used to estimate the SBLH. Next, a synergetic SBLH retrieval method is developed, which combines measurement data from both instruments. Finally, a preliminary study on the feasibility of Large Eddy Simulation (LES) as a tool for understanding the ABL is presented. To this end, LES-simulated lidar backscatter and potential temperature profiles are compared against instrumental measurements. In addition, a new method for direct retrieval of the MLH from LES-simulated brightness temperature measurements is presented, hence, alleviating the need for physical temperature retrieval first. The impact of retrieval errors on MLH estimates is also investigated. The techniques developed in this Ph.D. have been tested in the HOPE measurement campaign (Jülich, Germany), where different test cases under different atmospheric conditions have been considered. |
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