Ville Kangas

Microwave hyperspectral measurements for temperature and humidity atmospheric profiling from satellite: The clear‐sky case

This study investigates the benefits of a satellite HYperspectral Microwave Sensor (HYMS) for the retrieval of atmospheric temperature and humidity profiles, in the context of numerical weather prediction (NWP). In the infrared, hyperspectral instruments have already improved the accuracy of NWP forecasts. Microwave instruments so far only provide observations for a limited number of carefully selected channels. An information content analysis is conducted here to assess the impact of hyperspectral microwave measurements on the retrieval of temperature and water vapor profiles under clear-sky conditions. It uses radiative transfer simulations over a large variety of atmospheric situations. It accounts for realistic observation (instrument and radiative transfer) noise and for a priori information assumptions compatible with NWP practices. The estimated retrieval performance of the HYMS instrument is compared to those of the microwave instruments to be deployed on board the future generation of European operational meteorological satellites (MetOp-SG). The results confirm the positive impact of a HYMS instrument on the atmospheric profiling capabilities compared to MetOp-SG. Temperature retrieval uncertainty, compared to a priori information, is reduced by 2 to 10%, depending on the atmospheric height, and improvement rates are much higher than what will be obtained with MetOp-SG. For humidity sounding these improvements can reach 30%, a significant benefit as compared to MetOp-SG results especially below 250 hPa. The results are not very sensitive to the instrument noise, under our assumptions. The main impact provided by the hyperspectral information originates from the higher resolution in the O2 band around 60 GHz. The results are presented over ocean at nadir, but similar conclusions are obtained for other incidence angles and over land. Key Points A hyperspectral MW instrument could improve temperature & humidity retrieval compared to MetOp-SG The main impact from HYMS comes from higher resolution in the O2 band around 60 GHz Hyperspectral information is not really sensitive to instrument noise.

Biomass, CoReH 2 O, PREMIER: ESA's candidate 7 th Earth Explorer Missions

The European Space Agency (ESA) released a Call for Proposals for the next Earth Explorer Core Mission in March 2005, with the aim to select the 7th Earth Explorer (EE-7) mission for launch in the next decade [1]. Twenty-four proposals were received and subject to scientific and technical assessment. Six candidate missions were selected and further investigated in the preliminary feasibility studies (Phase 0). A further down-selection was made after the User Consultation Meeting held in Lisbon, Portugal in January 2009. Three candidate missions were selected for further feasibility investigations (phase A). Each of the candidate missions is now being defined in detail through two parallel and competing industrial studies and many complementary science and technology studies, aiming to the final down-selection in 2011/12, followed by the mission implementation with a planned launch in the 2016/17 timeframe.

Submillimetre-wave receiver developments for ICI onboard MetOP-SG and ice cloud remote sensing instruments

The development of heterodyne receiver channels at frequencies ranging from 183 GHz up to 664 GHz, and compatible with the requirements of both the ICI instrument onboard MetOp-SG and the ISMAR instrument onboard the FAAM aircraft are presented. In order to optimize the performance VS cost factor, multi-channels architecture that enhances commonalities as well as maximum redundancies in the use of planar Schottky diode is adopted. The performance of each component is close if not at the state-of-the-art. For these receivers, broadband high power and high efficiency mutlipliers, and also high sensitivity subharmonic mixers are required. These developments are also possible thanks to the availability of novel test equipment systems such as VNA and Spectrum Analyser extenders up to 750 GHz in order to characterize fully each component. Performance of these submillimetre wave test equipment systems developed by RPG is also presented.

ESA's premier mission candidate: System and payload overview

The European Space Agency (ESA) is preparing candidates for the 7th Earth Explorer Core mission with the aim to select one of them to be launched towards the end of this decade. Earth Explorers are the backbone of the science and research element of ESAs Living Planet Programme, providing an important contribution to the global endeavour of understanding the Earth system, particularly in view of global climate change. Six candidate missions were selected and further investigated in the preliminary assessment studies (Phase 0). A further down-selection was made after the User Consultation Meeting held in Lisbon, Portugal in January 2009. Three candidate missions (Biomass, CoReH2O and PREMIER) were selected for further feasibility investigations (Phase A). Each of the candidate missions has been defined in detail through two parallel and competing industrial studies and many complementary science and technology studies, aiming to the final down-selection in 2013, followed by the mission implementation with a planned launch in 2019. This paper will give an overview of the observation requirements, satellite, payload and general status of the PREMIER mission.

Ultra low noise V-band down-converters for MetOp-SG

This paper reports on the current ultra-low noise V-band down-converter development carried out by Airbus DS SAS for MetOp-SG mission. These equipment will be flying onboard MicroWave Sounder (MWS) and the MicroWave imager (MWI).

LNA module reliability testing for the MetOp Second Generation satellites

The reliability of the equipment that will be used in the MetOp Second Generation satellites is crucial, since there are significant storage and in-operation times. To evaluate the reliability performance of these receivers ESA has set up projects to assess these issues in advance. The most critical parts within the receivers of the atmospheric sounder and imager instruments are identified to be the detectors and the low-noise amplifiers. These components have a dedicated reliability assessment program within the projects on module level and the results can help in evaluating the most critical reliability aspects that should be investigated more carefully. In this paper, the 54 GHz (V-band) and 118 GHz (F-band) low-noise amplifier module design and reliability test results are presented.

The cloud and precipitation airborne radiometer - Populating the international sub-millimetre airborne radiometer

An upgrade funded by the European Space Agency to the Met Office ISMAR instrument as a risk reduction for potential future spaceborne radiometers is described. This adds four channels between 118GHz and 664GHz, to measure cloud, precipitation, and cirrus cloud. The receivers are all heterodyne based, with multiplied local oscillators and sub-harmonic mixers. The manufacturing of the receivers is underway and testing of the overall channels is starting. This will be followed by integration of all the channels onto ISMAR. The integrated instrument is to have its test flight on the FAAM aircraft in November 2012 and the project is to conclude in early 2013.

Antenna technologies from 435 MHz to 356 GHz for ESA's candidate Earth Explorer satellite missions

As a result of down-selection after Phase 0 for the 7th Earth Explorer mission following the User Consultation Meeting held in Lisbon, Portugal in Jan 2009, three candidate missions were selected for further feasibility investigations (Phase A) [1]. Each of the candidate missions is now being defined in detail through two parallel and competing industrial system studies and supporting complementary science and technology studies, aiming to the final down-selection in 2012, followed by the mission implementation with a planned launch in the 2017 timeframe. The microwave payloads of those candidate missions cover the frequency range from 435 MHz to 356 GHz. The BIOMASS candidate mission aims to measure the global forest biomass at P-band (435 MHz) using the synthetic aperture radar (SAR) technique. Due to the long wavelength and large distance between the satellite and the Earth, a very large antenna aperture is required (50–100 m2). The CoReH2O candidate missions aims to quantitatively measure the global distribution of snow over land and sea ice at X-(9.6 GHz) and Ku-band (17.2 GHz) using the SAR technique. The PREMIER candidate mission, carrying an infrared limb sounder and a microwave limb sounder, the latter covering the frequency range of 313–356 GHz, aims to measure atmospheric composition in the upper Troposphere and lower Stratosphere. Three very distinct antenna technologies are required for enabling those satellite missions. This paper describes the different antenna concepts proposed and corresponding technology developments which are on-going.

Design of a sub-millimetre wave airborne demonstrator for observations of precipitation and ice clouds

The design of a sub-millimetre wave airborne demonstrator for the measurement of ice clouds and precipitation has been presented. Based upon the use of existing microwave instruments together with a new sub-millimetre wave instrument being developed by the UK Met Office, this new instrument suite will be used to verify the feasibility of the CIWSIR and GOMAS missions.