360 research outputs found
Coupled land surface and radiative transfer models for the analysis of passive microwave satellite observations
Soil moisture is one of the key variables controlling the water and energy exchanges between
Earth’s surface and the atmosphere. Therefore, remote sensing based soil moisture
information has potential applications in many disciplines. Besides numerical weather
forecasting and climate research these include agriculture and hydrologic applications like
flood and drought forecasting.
The first satellite specifically designed to deliver operational soil moisture products, SMOS
(Soil Moisture and Ocean Salinity), was launched 2009 by the European Space Agency
(ESA). SMOS is a passive microwave radiometer working in the L-band of the microwave
domain, corresponding to a frequency of roughly 1.4 GHz and relies on a new concept. The
microwave radiation emitted by the Earth’s surface is measured as brightness temperatures in
several look angles. A radiative transfer model is used in an inversion algorithm to retrieve
soil moisture and vegetation optical depth, a measure for the vegetation attenuation of the
soil’s microwave emission.
For the application of passive microwave remote sensing products a proper validation and
uncertainty assessment is essential. As these sensors have typical spatial resolutions in the
order of 40 – 50 km, a validation that relies solely on ground measurements is costly and
labour intensive. Here, environmental modelling can make a valuable contribution.
Therefore the present thesis concentrates on the question which contribution coupled land
surface and radiative transfer models can make to the validation and analysis of passive
microwave remote sensing products. The objective is to study whether it is possible to explain
known problems in the SMOS soil moisture products and to identify potential approaches to
improve the data quality.
The land surface model PROMET (PRocesses Of Mass and Energy Transfer) and the
radiative transfer model L-MEB (L-band microwave emission of the Biosphere) are coupled
to simulate land surface states, e.g. temperatures and soil moisture, and the resulting
microwave emission. L-MEB is also used in the SMOS soil moisture processor to retrieve soil
moisture and vegetation optical depth simultaneously from the measured microwave
emission. The study area of this work is the Upper Danube Catchment, located mostly in
Southern Germany.
Since model validation is essential if model data are to be used as reference, both models are
validated on different spatial scales with measurements. The uncertainties of the models are
quantified. The root mean squared error between modelled and measured soil moisture at
several measuring stations on the point scale is 0.065 m3/m3. On the SMOS scale it is 0.039
m3/m3. The correlation coefficient on the point scale is 0.84.
As it is essential for the soil moisture retrieval from passive microwave data that the radiative
transfer modelling works under local conditions, the coupled models are used to assess the
radiative transfer modelling with L-MEB on the local and SMOS scales in the Upper Danube
Catchment. In doing so, the emission characteristics of rape are described for the first time
and the soil moisture retrieval abilities of L-MEB are assessed with a newly developed LMEB
parameterization. The results show that the radiative transfer modelling works well
under most conditions in the study area. The root mean squared error between modelled and
airborne measured brightness temperatures on the SMOS scale is less than 6 – 9 K for the
different look angles.
The coupled models are used to analyse SMOS brightness temperatures and vegetation optical
depth data in the Upper Danube Catchment in Southern Germany. Since the SMOS soil
moisture products are degraded in Southern Germany and in different other parts of the world
these analyses are used to narrow down possible reasons for this.
The thorough analysis of SMOS brightness temperatures for the year 2011 reveals that the
quality of the measurements is degraded like in the SMOS soil moisture product. This points
towards radio frequency interference problems (RFI), that are known, but have not yet been
studied thoroughly. This is consistent with the characteristics of the problems observed in the
SMOS soil moisture products. In addition to that it is observed that the brightness
temperatures in the lower look angles are less reliable. This finding could be used to improve
the brightness temperature filtering before the soil moisture retrieval.
An analysis of SMOS optical depth data in 2011 reveals that this parameter does not contain
valuable information about vegetation. Instead, an unexpected correlation with SMOS soil
moisture is found. This points towards problems with the SMOS soil moisture retrieval,
possibly under the influence of RFI.
The present thesis demonstrates that coupled land surface and radiative transfer models can
make a valuable contribution to the validation and analysis of passive microwave remote
sensing products. The unique approach of this work incorporates modelling with a high
spatial and temporal resolution on different scales. This makes detailed process studies on the
local scale as well as analyses of satellite data on the SMOS scale possible. This could be
exploited for the validation of future satellite missions, e.g. SMAP (Soil Moisture Active and
Passive) which is currently being prepared by NASA (National Aeronautics and Space
Administration). Since RFI seems to have a considerable influence on the SMOS data due to
the gained insights and the quality of the SMOS products is very good in other parts of the
world, the RFI containment and mitigation efforts carried out since the launch of SMOS
should be continued
Coupled land surface and radiative transfer models for the analysis of passive microwave satellite observations
Soil moisture is one of the key variables controlling the water and energy exchanges between
Earth’s surface and the atmosphere. Therefore, remote sensing based soil moisture
information has potential applications in many disciplines. Besides numerical weather
forecasting and climate research these include agriculture and hydrologic applications like
flood and drought forecasting.
The first satellite specifically designed to deliver operational soil moisture products, SMOS
(Soil Moisture and Ocean Salinity), was launched 2009 by the European Space Agency
(ESA). SMOS is a passive microwave radiometer working in the L-band of the microwave
domain, corresponding to a frequency of roughly 1.4 GHz and relies on a new concept. The
microwave radiation emitted by the Earth’s surface is measured as brightness temperatures in
several look angles. A radiative transfer model is used in an inversion algorithm to retrieve
soil moisture and vegetation optical depth, a measure for the vegetation attenuation of the
soil’s microwave emission.
For the application of passive microwave remote sensing products a proper validation and
uncertainty assessment is essential. As these sensors have typical spatial resolutions in the
order of 40 – 50 km, a validation that relies solely on ground measurements is costly and
labour intensive. Here, environmental modelling can make a valuable contribution.
Therefore the present thesis concentrates on the question which contribution coupled land
surface and radiative transfer models can make to the validation and analysis of passive
microwave remote sensing products. The objective is to study whether it is possible to explain
known problems in the SMOS soil moisture products and to identify potential approaches to
improve the data quality.
The land surface model PROMET (PRocesses Of Mass and Energy Transfer) and the
radiative transfer model L-MEB (L-band microwave emission of the Biosphere) are coupled
to simulate land surface states, e.g. temperatures and soil moisture, and the resulting
microwave emission. L-MEB is also used in the SMOS soil moisture processor to retrieve soil
moisture and vegetation optical depth simultaneously from the measured microwave
emission. The study area of this work is the Upper Danube Catchment, located mostly in
Southern Germany.
Since model validation is essential if model data are to be used as reference, both models are
validated on different spatial scales with measurements. The uncertainties of the models are
quantified. The root mean squared error between modelled and measured soil moisture at
several measuring stations on the point scale is 0.065 m3/m3. On the SMOS scale it is 0.039
m3/m3. The correlation coefficient on the point scale is 0.84.
As it is essential for the soil moisture retrieval from passive microwave data that the radiative
transfer modelling works under local conditions, the coupled models are used to assess the
radiative transfer modelling with L-MEB on the local and SMOS scales in the Upper Danube
Catchment. In doing so, the emission characteristics of rape are described for the first time
and the soil moisture retrieval abilities of L-MEB are assessed with a newly developed LMEB
parameterization. The results show that the radiative transfer modelling works well
under most conditions in the study area. The root mean squared error between modelled and
airborne measured brightness temperatures on the SMOS scale is less than 6 – 9 K for the
different look angles.
The coupled models are used to analyse SMOS brightness temperatures and vegetation optical
depth data in the Upper Danube Catchment in Southern Germany. Since the SMOS soil
moisture products are degraded in Southern Germany and in different other parts of the world
these analyses are used to narrow down possible reasons for this.
The thorough analysis of SMOS brightness temperatures for the year 2011 reveals that the
quality of the measurements is degraded like in the SMOS soil moisture product. This points
towards radio frequency interference problems (RFI), that are known, but have not yet been
studied thoroughly. This is consistent with the characteristics of the problems observed in the
SMOS soil moisture products. In addition to that it is observed that the brightness
temperatures in the lower look angles are less reliable. This finding could be used to improve
the brightness temperature filtering before the soil moisture retrieval.
An analysis of SMOS optical depth data in 2011 reveals that this parameter does not contain
valuable information about vegetation. Instead, an unexpected correlation with SMOS soil
moisture is found. This points towards problems with the SMOS soil moisture retrieval,
possibly under the influence of RFI.
The present thesis demonstrates that coupled land surface and radiative transfer models can
make a valuable contribution to the validation and analysis of passive microwave remote
sensing products. The unique approach of this work incorporates modelling with a high
spatial and temporal resolution on different scales. This makes detailed process studies on the
local scale as well as analyses of satellite data on the SMOS scale possible. This could be
exploited for the validation of future satellite missions, e.g. SMAP (Soil Moisture Active and
Passive) which is currently being prepared by NASA (National Aeronautics and Space
Administration). Since RFI seems to have a considerable influence on the SMOS data due to
the gained insights and the quality of the SMOS products is very good in other parts of the
world, the RFI containment and mitigation efforts carried out since the launch of SMOS
should be continued
The Old Sorrow
From 1969 to 1998, the conflict known as the Troubles raged in Northern Ireland, killing 3,500 people and devastating Belfast. Many dramatic adaptations tackle the conflict, from Neil Jordan’s Oscar-winning The Crying Game to Fifty Dead Men Walking. These adaptations usually focus on combatants in the conflict, however; none, to my knowledge, full address the experience of Belfast hospital staff, from doctors to nurses to porters. Hospital staff – especially those working at the Royal Victoria Hospital in Belfast, which lay at the edge of the Falls Road, an area keenly affected by the conflict – came from all sorts of backgrounds, both Catholic and Protestant, and had to navigate these questions of identity while trying to lives. My play, therefore, titled The Old Sorrow, explores the dramatically neglected role and experiences of these hospital staff, as well as the notion of the hospital as a microcosm or crucible for the conflict, a place where people from all sides were forced together.
More broadly, however, I seek to remedy a certain failing common to popular adaptations of the Troubles, which often dilute the complexities of the Northern Irish situation in favor of a streamlined, sensationalist narrative. One of the reasons for this, perhaps, is that while Neil Jordan is Irish himself, many of those heading other adaptations are not and, therefore, are automatically distanced, emotionally and politically, from the Troubles. Acknowledging my own authorial distance within the play itself – presenting the Troubles as honestly as I can while also being honest about my own experiences – is the more conceptual tightrope I walk while writing The Old Sorrow
INTEGRATING BIOMEDICAL AND PSYCHOSOCIAL APPROACHES TO STUDY PAIN IN PEDIATRIC SICKLE CELL DISEASE
Sickle cell disease (SCD) is a group of inherited blood disorders characterized by recurrent pain. A distinctive obstacle to managing pain in this condition is the substantial heterogeneity of outcomes observed in children, including the rate, intensity, duration, and extent of disability from pain. Previous studies have largely examined this heterogeneity by focusing on either biomedical or psychosocial approaches to this condition rather than pursuing an integrated approach that is consistent with modern conceptualizations of pain. In addition, few studies have examining genetic heterogeneity in pediatric SCD, which remains one of the only strategies for establishing a preventative approach to pain in this condition. In contrast to these approaches, the present project describes an integrated biomedical and psychosocial approach to studying pain in pediatric SCD that consisted of two studies: (a) a study that examined an integrated, biopsychosocial model of pain in SCD and (b) a study that examined a novel genetic marker of pain variability in SCD. The results from these studies are provided along with discussion, clinical implications, and future directions for this work
A dynamic approach for evaluating coarse scale satellite soil moisture products
Validating coarse scale remote sensing soil moisture products requires a comparison of gridded data to point-like ground measurements. The necessary aggregation of in situ measurements to the footprint scale of a satellite sensor (>100 km<sup>2</sup>) introduces uncertainties in the validation of the satellite soil moisture product. Observed differences between the satellite product and in situ data are therefore partly attributable to these aggregation uncertainties. The present paper investigates different approaches to disentangle the error of the satellite product from the uncertainties associated to the up-scaling of the reference data. A novel approach is proposed, which allows for the quantification of the remote sensing soil moisture error using a temporally adaptive technique. It is shown that the point-to-area sampling error can be estimated within 0.0084 [m<sup>3</sup>/m<sup>3</sup>]
On the sea anemone Paracondylactis hertwigi (Wassilieff, 1908)
É redescrita a espécie tipo do gênero Paracondylactis Carlgren, 1934 (Carlgren, 1934), P. hertwigi (Wassilieff, 1908), com base em espécimes provenientes da costa de São Paulo, Brasil.Uma comparação é feita com a primeira redescrição da espécie (Carlgren, 1934), assim como também com as outras duas espécies do gênero, P. sinensis Carlgren, 1934 (Carlgren, 1934) e P. dawydoffi Carlgren, 1943 (Carlgren, 1943).O gênero era conhecido até agora apenas de localidades do Leste Asiático
Phyllactis correae n.sp. (Cnidaria, Actiniaria, Actiniidae) from Atol das Rocas, Brazil, with notes on Phyllactis flosculifera (Lesueur, 1817)
Neste trabalho, descrevemos Phyllactis correae sp. n., provavelmente endêmica do Atol das Rocas, e registramos observações morfológicas, taxonómicas e biológicas sobre Phyllactis ilosculifera (Lesueur, 1817) Phyllactis correae sp. n. difere das demais espécies do gênero por: dimensões e colarinho menores e coloração mais clara, bem como pela ocorrência de um terceiro ciclo de mesentérios totalmente imperfeitos. Um exemplar utilizado para preparações histológicas era hermafrodita e continha plânulas; foi também observada localização anômala de gônadas em alguns exemplares. Sugerimos um adendo à diagnose do genero Phyllactis Milne—Edwards & Haime, 1851 feita por CARLGREN (1949): todos os mesentérios perfeitos ou perfeitos e imperfeitos, hexâmera e regularmente dispostos. Na discussão, além dos problemas taxonômicos, incluímos os aspectos biológicos já observados em ambas as espécies, bem como os relativos á sua distribuição geográfica
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