ALBERT

Description: In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion.

Description: Recent advancements of space geodetic observations and remote sensing techniques allow to extract hydrological information reasonably well at the river basin scale. Combining this information with in-situ data provide a new opportunity to explore the feasibility of assessing hydrological models at the basin scale. Appreciating such possibilities, a group of researchers from the different institutions in India, has developed a project that envisioned to quantify each component of hydrological cycle at the basin scale and also planned to investigate crustal deformations due to the hydrological changes. The project was financially supported by National Geospatial Programme, Department of Science and Technology, India. A precise assessment of Terrestrial Water Storage (TWS), groundwater storage, soil moisture, evapotranspiration, severity of drought and hot –spells at basin scale and downscaling of the GRACE derived TWS to the sub-basin scale are carried out under this project. Several GPS stations co-located with soil moisture probes are installed in the Ganga river basin to validate and improve the hydrological models. It is planned to present the results over three major river basins of India studied under this project.

Description: In the last decade, Alfvénic fluctuations remained a major focus of research on coronal heating and the origin of solar wind. Theoretical studies postulated that predominantly outward propagating waves carry a significant fraction of energy and momentum from the lower solar atmosphere and dissipate in corona via MHD turbulence, thereby heating the plasma and accelerating the solar wind. Perpendicular correlation length(s) is a key parameter of such Alfvénic turbulence driven models which can strongly influence energy dissipation below and above the sonic point, while affecting the observed thermal and kinetic energy profiles in the solar atmosphere and beyond. The correlation length appears to determine the heating rate and the mechanisms by which wave energy are dissipated. We present recent work where the magnitudes of the correlation lengths are estimated, for the first time, from observed transverse waves in the solar corona using Coronal Multi-Channel Polarimeter (CoMP) data for different magnetic topologies (open/closed). Our results provide a critical insight into the MHD turbulent energy injection scales associated with Alfvenic waves in the solar atmosphere and a clear constraint for future numerical Alfvén wave turbulence studies.

Description: In Nepal, majority of households still burn solid fuels in inefficient cook stoves inside poorly ventilated kitchens, which results in very high levels of indoor pollutants, including black carbon (BC). Previous studies have not yet reported BC concentrations in typical kitchen configurations in rural Nepal. In this study, fine particulate matter (PM) and BC concentrations were monitored continuously inside two types of kitchens (separated from and attached to the main house) under actual cooking practices. Prior to monitoring of pollutants, a field survey was conducted to gain insight into the types of kitchens, cook stoves and fuels used. Indoor PM and BC concentrations were monitored using biomass fuels in traditional cook stoves (TC) and improved cook stoves (ICS). Clear diurnal variations of the pollutants were observed in both kitchens, with the highest concentrations during cooking times. BC and PM concentrations during cooking and non-cooking periods demonstrated clear reductions in the concentrations during non-cooking periods. It was observed that the concentrations rose steeply during the first half hour of cooking, then decreased slightly and finally leveled off to the non-cooking period concentrations. 24-hour average indoor PM concentrations in both kitchens frequently exceeded Nepal's indoor air quality standards and the WHO PM2.5 guidelines, by a factor of ~8 to ~28. We found that the specific type of ICS used in this study, a commonly used ICS in Nepal and other developing countries might help in PM emission reductions but not necessarily BC emission reduction.