A5066871122- Atmospheric aerosols and clouds
- Meteorological Phenomena and Simulations
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Cryospheric studies and observations
- Precipitation Measurement and Analysis
- Climate variability and models
- Arctic and Antarctic ice dynamics
- Atmospheric and Environmental Gas Dynamics
- Calibration and Measurement Techniques
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Remote-Sensing Image Classification
- Tropical and Extratropical Cyclones Research
- Methane Hydrates and Related Phenomena
- Ocean Waves and Remote Sensing
- Medical Imaging Techniques and Applications
- Advanced MRI Techniques and Applications
- Aerospace Engineering and Energy Systems
- Solar and Space Plasma Dynamics
Swedish Meteorological and Hydrological Institute
2023-2024
FoU Södertörn
2020
Chalmers University of Technology
2006-2011
A passive satellite radiometer operating at submillimetre wavelengths can measure cloud ice water path (IWP), particle size, and altitude. The paper first discusses the scientific background for such measurements. Formal mission requirements are derived, based on this earlier assessments. then presents a comprehensive prototype instrument concept, demonstrates that it meets requirements. is conically scanning 12-channel with channels between 183 664 GHz, proposed to fly in tandem one of...
Abstract. The second generation of the EUMETSAT Polar System (EPS-SG) will include Ice Cloud Imager (ICI), first operational sensor covering sub-millimetre wavelengths. Three copies ICI be launched that together give a measurement time series exceeding 20 years. Due to novelty ICI, preparing data processing is especially important and challenging. This paper focuses on activities related product planned, but also presents basic technical characteristics instrument. A retrieval algorithm...
Abstract. A neural-network-based method, quantile regression neural networks (QRNNs), is proposed as a novel approach to estimating the posteriori distribution of Bayesian remote sensing retrievals. The advantage QRNNs over conventional network retrievals that they learn predict not only single retrieval value but also associated, case-specific uncertainties. In this study, performance characterized and compared other state-of-the-art methods. synthetic scenario presented used validation...
The performance of a conically scanning satellite instrument for the measurement cloud ice was studied. measures radiances in 12 channels placed around 183, 325 and 448 GHz water vapour lines 243, 664 874 window channels, is designed to provide estimations path (IWP), equivalent sphere diameter (DME), median mass height (ZME). Overall relative errors 20% IWP, 33 µm DME, 240 m ZME midlatitude winter scenario, 17% 30 310 tropical scenario were found. Detection limits (relative retrieval error...
Abstract. More accurate global measurements of the amount ice in thicker clouds are needed to validate atmospheric models and sub-mm radiometry can be an important component this respect. A cloud retrieval scheme for first such instrument space, Odin-SMR, is presented here. Several advantages observations shown, as low influence particle shape orientation, a high dynamic range retrievals. In case only above ≈12.5 km measured. The present gives detection threshold about 4 g/m2 12.5 does not...
Abstract. The Arctic Weather Satellite (AWS) is a project led by the European Space Agency (ESA) that has several novel aspects. From technical perspective, it serves as demonstrator of how to expand network operational satellite-based microwave sensors cost-effectively and acts proto-flight model for suggested constellation satellites, denoted EUMETSAT Polar System (EPS) Sterna. design philosophy been reduce complexity instead focus efforts on critical parts characterise instrument well...
Abstract. The paper presents a cloud filtering method for upper tropospheric humidity (UTH) measurements at 183.31±1.00 GHz. uses two criteria: viewing angle dependent threshold on the brightness temperature GHz, and difference between another channel Two different alternatives, using 183.31±3.00 GHz or 183.31±7.00 as other channel, are studied. robustness of this is demonstrated by mid-latitudes winter case study. then studies biases UTH climatologies. Clouds associated with high humidity,...
Abstract. Collocations between two satellite sensors are occasions where both observe the same place at roughly time. We study collocations Microwave Humidity Sounder (MHS) on-board NOAA-18 and Cloud Profiling Radar (CPR) CloudSat. First, a simple method is presented to obtain those this compared with more complicated approach found in literature. present statistical properties of collocations, particular attention effects differences footprint size. For 2007, we find approximately half...
Abstract. Odin-SMR is a limb-sounder operating in the 500 GHz region with capability of performing measurements down to altitudes about 10 km relatively low influence ice clouds. Until now spectra from tropospheric tangent have been disregarded due inadequate handling scattering. A first method extract upper quantities has developed, yielding humidity two layers around 200 and 130 hPa information on cloud content above hPa. First results are compared situ MOZAIC presented give global view...
Abstract. Emerging microwave satellite techniques are expected to provide improved global measurements of cloud ice mass. CloudSat, Aura MLS and Odin-SMR fall into this category early retrievals from these instruments compared. The comparison follows the SMR retrieval product is made for partial water columns above 12 km. None shows a significant degree false detections, ratio between local mean values fairly constant consistent view geographical distribution obtained. However, important...
Abstract. Improved Odin-SMR retrievals of upper tropospheric water are presented. The new retrieval algorithm retrieves humidity and cloud ice mass simultaneously takes into account inhomogeneities. Both these aspects introduced for microwave limb sounding inversions the first time. A Bayesian methodology is applied allowing a formally correct treatment non-unique problems involving non-Gaussian statistics. Cloud structure information from CloudSat incorporated algorithm. This removes major...
Abstract. Observational results of diurnal variations humidity from Odin-SMR and AURA-MLS, cloud ice mass CloudSat are presented for the first time. Comparisons show that retrievals these two satellite combinations in good agreement. The retrieved data combined four almost evenly distributed times day allowing mean values, amplitudes phases around 200 hpa to be estimated. This analysis is applied six climatologically distinct regions, five located tropics one over subtropical northern...
Abstract. Retrievals of cloud ice mass and humidity from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) Odin-SMR (Sub-Millimetre Radiometer) limb sounder are presented example applications data given. SMILES give an unprecedented view diurnal variation mass. Mean regional cycles reported compared to some global climate models. Some improvements in models regarding timing relative amplitude were noted, but models' mean around 250 hPa is still low observations. The...
Submillimetre down-looking radiometry is a promising technique for global measurements of cloud ice properties. There exist no observation data sufficient size that can be used detailed pre-launch studies such an instrument and other means must found to obtain optimise the design similar tasks. Several aspects observations make traditional retrieval methods not suitable nonlinear multidimensional regression techniques (e.g. Bayesian Monte Carlo integration neural networks) applied. Such are...
Abstract. The Sub-Millimetre Radiometer (SMR) on board the Odin satellite performs limb sounding measurements of middle atmosphere to detect molecular emission from different species. Carbon monoxide (CO) is an important tracer atmospheric dynamics at these altitudes, due its long photochemical lifetime and high vertical concentration gradient. In this study, we have successfully recovered over 18 years SMR observations, providing only dataset date being so extended in time stretching out...
Abstract. Microwave limb sounding in the presence of ice clouds was studied by detailed simulations, where and other atmospheric variables varied three dimensions full polarisation state considered. Scattering particles were assumed to be horizontally aligned oblate spheroids with a size distribution parameterized terms temperature water content. A general finding that particle absorption is significant for sounding, which contrast down-looking case, it usually insignificant. Another single...
Abstract. The second generation of the EUMETSAT Polar System (EPS-SG) will include Ice Cloud Imager (ICI), first operational sensor covering sub-millimetre wavelengths. Three copies ICI be launched that together give a measurement series exceeding 20 years. Due to novelty ICI, preparing data processing is especially important and challenging. This paper focuses on activities related product planned, but also presents basic technical characteristics instrument. A retrieval algorithm based...
Abstract. The Ice Cloud Imager (ICI) aboard the Second Generation of EUMETSAT Polar System (EPS-SG) will provide novel measurements ice hydrometeors. ICI is a passive conically scanning radiometer that operate within frequency range 183 GHz to 664 GHz, helping cover present wavelength gap between microwave and infrared observations. Reliable global data be produced on daily basis. This paper presents retrieval database used operationally performs final pre-launch assessment retrievals....
The forthcoming spaceborne ice cloud imager (ICI) millimeter/submillimeter-wave radiometer is designed to support climate monitoring and clouds representation in weather models. assessment of the correct pointing each ICI channel undeniable importance deliver high-quality products. Nevertheless, channels have a limited chance sample surface features due strong atmospheric gas absorption. Only for within 183–325 GHz, few locations worldwide show sufficiently dry environmental conditions...
Abstract. Its long photochemical lifetime makes H2O a good tracer for mesospheric dynamics. Temperature observations are also critical to study middle atmospheric In this study, we present the reprocessing of 18 years and temperature measurements from Sub-Millimetre Radiometer (SMR) aboard Odin satellite, resulting in part SMR version 3.0 level 2 data set. The previous set showed poor accordance with other instruments, which suggested that retrieved concentrations were subject instrumental...
The forthcoming spaceborne Ice Cloud Imager (ICI) radiometer has 11 channels in the millimeter (mm) and sub-mm wave range from 183 up to 664 GHz. At some of these frequencies, atmosphere is very opaque due strong gaseous cloud extinction, precluding observation surface. We aim at investigating how evaluate ICI geolocation error using surface landmark targets. most transparent channels, i.e., those around 183.3 ± 7.0 GHz vertical (V) polarization (ICI-1) 243.2 2.5 (ICI-4) horizontal (H)/ V...
Abstract. The paper presents a cloud filtering method for upper tropospheric humidity (UTH) measurements at 183.31±1.00 GHz. uses two criteria: difference between the brightness temperatures 183.31±7.00 and GHz, threshold temperature robustness of this filter is demonstrated by mid-latitudes winter case-study. then studies different biases on UTH climatologies. Clouds are associated with high humidity, therefore dry bias introduced discussed compared to wet clouds radiative effect if no...