Multi year measurements of surface-reaching solar (shortwave) radiation fluxes across a network of aerosol observatories (ARFINET) are combined with concurrent satellite (CERES)-based top of the atmosphere (TOA) fluxes to estimate regional aerosol direct radiative forcing (ARF) over the Indian region. The synergistic approach improves the accuracy of ARF estimates, which otherwise results in an overestimation or underestimation of the atmospheric forcing. During summer, an overestimation of similar to 5 W m(-2) (corresponding heating rate similar to 0.15 K day(-1)) is noticed. The regional average ARF from the synergistic approach reveals the surface forcing reaching -49 W m(-2) over the Indo Gangetic Plains, -45 W m(-2) over northeast India, -34 W m(-2) over the southern Peninsula, and - 16 W m(-2) in the oceanic regions of the Bay of Bengal. The ARF over the northern half of the Indian subcontinent is influenced mainly by anthmpogenic sulfate and carbonaceous aerosols. Dust is dominant in the western region of India during MAM and JJAS. Overall, the clear sky surface reaching solar radiation fluxes is reduced by 3-22% due to the abundance of aerosols in the atmosphere, with the highest reduction over the IGP during autumn and winter.

Water ice, abundant in the outer solar system, is volatile in the inner solar system. On the largest airless bodies of the inner solar system (Mercury, the Moon, Ceres), water can be an exospheric species but also occurs in its condensed form. Mercury hosts water ice deposits in permanently shadowed regions near its poles that act as cold traps. Water ice is also present on the Moon, where these polar deposits are of great interest in the context of future lunar exploration. The lunar surface releases either OH or H2O during meteoroid showers, and both of these species are generated by reaction of implanted solar wind protons with metal oxides in the regolith. A consequence of the ongoing interaction between the solar wind and the surface is a surficial hydroxyl population that has been observed on the Moon. Dwarf planet Ceres has enough gravity to have a gravitationally-bound water exosphere, and also has permanently shadowed regions near its poles, with bright ice deposits found in the most long-lived of its cold traps. Tantalizing evidence for cold trapped water ice and exospheres of molecular water has emerged, but even basic questions remain open. The relative and absolute magnitudes of sources of water on Mercury and the Moon remain largely unknown. Exospheres can transport water to cold traps, but the efficiency of this process remains uncertain. Here, the status of observations, theory, and laboratory measurements is reviewed.

Twelve years of NASA CERES (Clouds and Earth's Radiant Energy System) data have been used to examine the spatio-temporal variability of aerosol - and cloud - induced shortwave radiative forcing over selected hot spot regions in India. Four regions (northern semiarid - R1; monsoon trough - R2; densely populated urban - R3; and southern peninsula - R4) are selected with different surface characteristics and notable difference in meteorological and geographical features. The analysis shows that three out of the four regions (viz. R1, R2, and R3) experience high aerosol loading and forcing in the monsoon season followed by moderate forcing in pre-monsoon season. While all the seasons except the post-monsoon period show a positive linear relation between cloud optical depth and aerosol optical depth for all the regions, the post-monsoon season shows a negative relation. However, the relation between aerosol forcing and cloud forcing shows adequate non-linearity owing to the numerous factors that control cloud radiative effect. The estimated aerosol induced heating rate shows exponential decrease with height, but with high variability during each season. Irrespective of any region, the maximum heating rate is observed in the pre-monsoon season (2.86 +/- 0.78, 2.49 +/- 0.78, 1.89 +/- 0.57, and 0.88 +/- 0.28 K/day for R1, R2, R3, and R4, respectively). Plausible reasons for the variation in the above parameters are discussed. The results suggest that increased anthropogenic activities affect the thermodynamics and hence the dynamics through retention and exchange of heat, and it could affect the precipitation pattern adversely. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.

After Vesta, the NASA Dawn spacecraft will visit the dwarf planet Ceres to carry out in-depth observations of its surface morphology and mineralogical composition in 2015. One of the important questions is whether Ceres has any outgassing activity that would lead to the formation of a thin atmosphere. The recent detection of water vapor emitted from localized source regions by Herschel (Kuppers et al., 2014) has only underscored this point. If the localized outgassing activity observed by Herschel is totally switched off, could a sizable surface-bounded exosphere still be maintained by other source mechanisms? Our preliminary assessment is that chemical sputtering via solar wind interaction and meteoroid impact are probably not adequate because of the large injection speed of the gas at production relative to the surface escape velocity of Ceres. One potential source is a low-level outgassing effect from its subsurface due to thermal sublimation with a production rate of the order of 10(24) molecules s(-1) as first considered by Fanale and Salvail (1989). If the water plumes are active, the fall-back of some of the water vapor onto Ceres' surface would provide an additional global source of water molecules on the surface with a production rate of about 10(25) molecules s(-1) In this work, different scenarios of building up a tenuous exosphere by ballistic transport and the eventual recycling of the water molecules to the polar cold trap are described. It turns out that a large fraction of the exospheric water could be transferred to the polar caps area as originally envisaged for the lunar polar ice storage. (C) 2014 Elsevier Ltd. All rights reserved.

The question whether life originated on Earth or elsewhere in the solar system has no obvious answer, since Earth was sterilized by the Moon-forming impact and possibly also during the LHB, about 700 Ma after the formation of the solar system. Seeding by lithopanspermia has to be considered. Possible sources of life include Earth itself, Mars, Venus (if it had a more benign climate than today) and icy bodies of the solar system. The first step of lithopanspermia is the ejection of fragments of the surface into space, which requires achieving at least escape velocity. As the velocity distribution of impact ejecta falls off steeply, attention is drawn to bodies with lower escape velocities. Ceres has had, or still has, an ocean more than 100 km deep, with hydrothermal activity at its rocky core. The possible presence of life, its relative closeness to the terrestrial planets and Ceres' low escape velocity of 510 m/s suggest that Ceres could well be a parent body for life in the solar system. Icy impact ejecta - hence glaciopanspermia - from Ceres will be subject to evaporation of volatiles. Spores may be loosened by evaporation and enter the atmospheres of the terrestrial planets as micrometeorites. The seeding of the terrestrial planets from Ceres would result in (1) detection of life in the crustal layers of Ceres; (2) a commonality of Cerean life with Terran and possible Martian and Venusian life and (3) biomarkers of Cerean life, which might be found in the ice at the Moon's poles and on the surface of other main belt asteroids. (C) 2010 Elsevier Ltd. All rights reserved.