Helioseismic Mapping of the Magnetic Canopy in the Solar Chromosphere

We determine the three-dimensional topography of the magnetic canopy in and around active regions by mapping the propagation behavior of high-frequency acoustic waves in the solar chromosphere

How Big Data Can Help to Monitor the Environment and to Mitigate Risks due to Climate Change:A review

Climate change triggers a wide range of hydrometeorological, glaciological, and geophysical processes that span across vast spatiotemporal scales. With the advances in technology and analytics, a multitude of remote sensing (RS), geodetic, and in situ instruments have been developed to effectively monitor and help comprehend Earth’s system, including its climate variability and the recent anomalies associated with global warming. A huge volume of data is generated by recording these observations, resulting in the need for novel methods to handle and interpret such big datasets. Managing this enormous amount of data extends beyond current computer storage considerations; it also encompasses the complexities of processing, modeling, and analyzing. Big datasets present unique characteristics that set them apart from smaller datasets, thereby posing challenges to traditional approaches. Moreover, computational time plays a crucial role, especially in the context of geohazard warning and response systems, which necessitate low latency requirements

Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

A large number of radiometers are traceable to the World Standard Group (WSG) for shortwave radiation and the interim World Infrared Standard Group (WISG) for longwave radiation, hosted by the Physikalisch-Meteorologisches Observatorium Davos/World Radiation Centre (PMOD/WRC, Davos, Switzerland). The WSG and WISG have recently been found to over- and underestimate radiation values, respectively (Fehlmann et al., 2012; Gröbner et al., 2014), although research is still ongoing. In view of a possible revision of the reference scales of both standard groups, this study discusses the methods involved and the implications on existing archives of radiation time series, such as the Baseline Surface Radiation Network (BSRN). Based on PMOD/WRC calibration archives and BSRN data archives, the downward longwave radiation (DLR) time series over the 2006–2015 period were analysed at four stations (polar and mid-latitude locations). DLR was found to increase by up to 3.5 and 5.4 W m−2 for all-sky and clear-sky conditions, respectively, after applying a WISG reference scale correction and a minor correction for the dependence of pyrgeometer sensitivity on atmospheric integrated water vapour content. Similar increases in DLR may be expected at other BSRN stations. Based on our analysis, a number of recommendations are made for future studies.ISSN:1867-1381ISSN:1867-854

The TSI record from PREMOS/PICARD

International audienceSince the launch of PICARD in 2010 the PMO6 absolute radiometers of the PREMOS experiment had been measuring Total Solar Irradiance. We will present the TSI data record, corrected for sensor degradation, and review the stability of the radiometers during the entire mission. Implications for the uncertainty of Composite Total Solar Irradiance time Series data sets will be discussed

Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer (PREMOS/PICARD)

The switching of the total solar irradiance (TSI) backup radiometer (PREMOS-B) to a primary role for 2 weeks at the end of the PICARD mission provides a unique opportunity to test the fundamental hypothesis of radiometer experiments in space, which is that the sensitivity change of instruments due to the space environment is identical for the same instrument type as a function of solar-exposure time of the instruments. We verify this hypothesis for the PREMOS TSI radiometers within the PREMOS experiment on the PICARD mission. We confirm that the sensitivity change of the backup instrument, PREMOS-B, is similar to that of the identically-constructed primary radiometer, PREMOS-A. The extended exposure of the backup instrument at the end of the mission allows for the assessment, with an uncertainty estimate, of the sensitivity change of the primary radiometer from the beginning of the PICARD mission compared to the end, and of the degradation of the backup over the mission. We correct six sets of PREMOS-B observations connecting October 2011 with February 2014, using six ratios from simultaneous PREMOS-A and PREMOS-B exposures during the first days of PREMOS-A operation in 2010. These ratios are then used, without indirect estimates or assumptions, to evaluate the stability of SORCE/TIM and SOHO/VIRGO TSI measurements, which have both operated for more than a decade and now show different trends over the time span of the PICARD mission, namely from 2010 to 2014. We find that by February 2014 relative to October 2011 PREMOS-B supports the SORCE/TIM TSI time evolution, which in May 2014 relative to October 2011 is ~0.11 W m−2, or ~84 ppm, higher than SOHO/VIRGO. Such a divergence between SORCE/TIM and SOHO/VIRGO over this period is a significant fraction of the estimated decline of 0.2 W m−2 between the solar minima of 1996 and 2008, and questions the reliability of that estimated trend. Extrapolating the uncertainty indicated by the disagreement of SORCE/TIM and PREMOS with respect to SOHO/VIRGO, we can conclude that it is currently not possible to assess centennial timescale changes in solar irradiance based on any of the presently existing TSI composites. It is imperative to accurately estimate solar irradiance changes from observations in order to extrapolate centennial scale trends important for understanding both long-term solar irradiance changes and the Sun’s influence on the Earth’s climate

Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer (PREMOS/PICARD)

The switching of the total solar irradiance (TSI) backup radiometer (PREMOS-B) to a primary role for 2 weeks at the end of the PICARD mission provides a unique opportunity to test the fundamental hypothesis of radiometer experiments in space, which is that the sensitivity change of instruments due to the space environment is identical for the same instrument type as a function of solar-exposure time of the instruments. We verify this hypothesis for the PREMOS TSI radiometers within the PREMOS experiment on the PICARD mission. We confirm that the sensitivity change of the backup instrument, PREMOS-B, is similar to that of the identically-constructed primary radiometer, PREMOS-A. The extended exposure of the backup instrument at the end of the mission allows for the assessment, with an uncertainty estimate, of the sensitivity change of the primary radiometer from the beginning of the PICARD mission compared to the end, and of the degradation of the backup over the mission. We correct six sets of PREMOS-B observations connecting October 2011 with February 2014, using six ratios from simultaneous PREMOS-A and PREMOS-B exposures during the first days of PREMOS-A operation in 2010. These ratios are then used, without indirect estimates or assumptions, to evaluate the stability of SORCE/TIM and SOHO/VIRGO TSI measurements, which have both operated for more than a decade and now show different trends over the time span of the PICARD mission, namely from 2010 to 2014. We find that by February 2014 relative to October 2011 PREMOS-B supports the SORCE/TIM TSI time evolution, which in May 2014 relative to October 2011 is ~0.11 W m−2, or ~84 ppm, higher than SOHO/VIRGO. Such a divergence between SORCE/TIM and SOHO/VIRGO over this period is a significant fraction of the estimated decline of 0.2 W m−2 between the solar minima of 1996 and 2008, and questions the reliability of that estimated trend. Extrapolating the uncertainty indicated by the disagreement of SORCE/TIM and PREMOS with respect to SOHO/VIRGO, we can conclude that it is currently not possible to assess centennial timescale changes in solar irradiance based on any of the presently existing TSI composites. It is imperative to accurately estimate solar irradiance changes from observations in order to extrapolate centennial scale trends important for understanding both long-term solar irradiance changes and the Sun’s influence on the Earth’s climate