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The article offers information on the global acknowledgment of climate change as a reality caused by human intervention, with topics including the consequences of climate change, regional and global environmental concerns, and unique challenges faced by India, particularly the receding Sundarbans mangrove forest.

The article discusses the need for rural electrification using hybrid solar-wind energy systems to address the challenges of climate change and increasing energy demand in India. Topics include the rise in greenhouse gas concentrations; the importance of renewable energy sources like solar and wind; and the role of hybrid energy systems in providing a balanced solution for rural electrification while reducing the impact on climate.

Climate change has great significance in Asia in general, and India in particular; and atmospheric aerosols have a decisive role in this. The climate forcing potential of aerosols is closely linked to their optical, microphysical and chemical properties. Systematic efforts to characterize these properties over the Indian region started about 5 decades ago, and evolved over the years through concerted efforts in the form of long-term scientific programmes as well as concerted fields experiments. All these have resulted in this activity becoming one of the most vibrant fields of climate research in India and have brought several important issues in the national and international foci. The field experiment, RAWEX--GVAX (Regional Aerosol Warming Experiment--Ganges Valley Aerosol Experiment), conducted during 2011-12 jointly by the US Department of Energy, Indian Space Research Organization and Department of Science and Technology, has emerged as a direct outcome of the above efforts. This overview provides a comprehensive account of the development of aerosol--climate research in India and south Asia, and the accomplishment and newer issues that warranted the above field campaign. Details of RAWEX--GVAX, the major outcomes and the subsequent and more recent efforts are presented, followed by the way forward in this field for the next several years to come. [ABSTRACT FROM AUTHOR]

During a series of measurements, simultaneous measurements were made of spectral aerosol optical depths (AOD), black carbon (BC) mass concentration, total and size segregated composite aerosol mass concentrations at the second campus of Indian Institute of Science (IISc), Challakere, Karnataka. Surprisingly, most of the aerosol mass is found in the submicron size range, which is unusual for a dry region. Unexpectedly large enhancement in BC aerosol concentration was observed during the morning hours (6-8 a.m.), both during summer and winter, which is mysterious and hence requires further study. However, BC mass fraction, which is one of the most important climaterelevant parameters was 3.3% of total aerosol mass, implying a significantly low aerosol-induced absorption of solar radiation and hence consequent atmospheric warming. Based on our initial measurements as well as 11 years of satellite data analysis, we conclude that this location is best suited for establishing a climate observatory. [ABSTRACT FROM AUTHOR]

Knowledge of aerosol radiative forcing over land is essential to answer crucial questions related to climate change. Retrieval of aerosol properties over land is complicated due to irregular terrain characteristics and high surface reflection. The retrieval of algorithms used in conventional satellite sensors for continental regions is not completely free from the high reflectance effect and hence leads to large uncertainties in the retrieved parameters. We propose a dedicated satellite sensor namely multi-angle polarization imager (MAPI). The main characteristic of MAPI is multi-spectral and multi-angle measurements of polarized components of reflected radiation from the Earth. The proposed sensor has capability of aerosol retrieval over land. The sensor also has the ability to discriminate dust aerosols (which is the major natural aerosol over land) from other aerosols (using infrared radiance). This is the first step towards separating natural and anthropogenic aerosols, which is needed for the scientific community at large. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses articles in the issue including field observations to understand temperature and precipitation changes in the Himalayas, mass balance and ice thickness in assessing the effect of changing climate, and mass loss analysis by geodetic method.

The spatial patterns of rainfall and rain systems during El Niño and La Niña episodes are distinctly different due to the longitudinal variations in the Walker circulation ascent/decent branches over India and adjoining Oceans. In order to examine these differences, 16 years (1998-2013) of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data have been utilized. TRMM-PR delineated precipitating systems (convective, stratiform and shallow) show distinctly different spatial structures over India and adjoining Oceans during El Niño and La Niña episodes. During the El Niño episode, the occurrence of deep systems is high over north of 20°N latitude, and shallow systems are plentiful over south of 20°N latitude. On the other hand, during the La Niña episodes, the occurrence of shallow systems is in excess over Pakistan, central India, northwest Arabian Sea, southwest Indian Ocean and northern Bay of Bengal while the deep systems are abundant over west coast of India, Ganges basin, eastern Indian Ocean and Arabian Sea. The excess convective rain pixels observed during El Niño years are from deep and deep and wide convective core systems due to increase in the CAPE, nevertheless the broad stratiform rain systems are prevalent during La Niña years due to the high convergence of moisture flux and mid-tropospheric upward motion. Though the convective occurrence is more, their intensity is weaker during El Niño years than during La Niña years, indicating the intense nature of convective storms during La Niña episodes. [ABSTRACT FROM AUTHOR]

During the second phase of the Arabian Sea Monsoon Experiment (ARMEX-II), extensive measurements of spectral aerosol optical depth, mass concentration, and mass size distribution of ambient aerosols as well as mass concentration of aerosol black carbon (BC) were made onboard a research vessel during the intermonsoon period (i.e., when the monsoon winds are in transition from northeasterlies to westerlies/southwesterlies) over the Arabian Sea (AS) adjoining the Indian Peninsula. Simultaneous measurements of spectral aerosol optical depths (AODs) were made at different regions over the adjoining Indian landmass. Mean AODs (at 500-nm wavelength) over the ocean (∼0.44) were comparable to those over the coastal land (∼0.47), but were lower than the values observed over the plateau regions of central Indian Peninsula (∼0.61). The aerosol properties were found to respond distinctly with respect to change in the trajectories, with higher optical depths and flatter AOD spectra associated with trajectories indicating advection from west Asia, and northwest and west-coastal India. On average, BC constituted only ∼2.2% to total aerosol mass compared to the climatological values of ∼6% over the coastal land during the same season. These data are used to characterize the physical properties of aerosols and to assess the resulting short-wave direct aerosol forcing. The mean values were –27 W m-2 at the surface and -12 W m-2 at the top of the atmosphere (TOA), resulting in a net atmospheric forcing of +15 W m-2. The forcing also depended on the region from where the advection predominates. The surface and atmospheric forcing were in the range -40 to -57 W m-2 and +27 to +39 W m-2, respectively, corresponding to advection from the west Asian and western coastal India where they were as low as -19 and +10 W m-2, respectively, when the advection was mainly from the Bay of Bengal and from central/peninsular India. In all these cases, the net atmospheric forcing (heating) efficiency was lower than the values reported for northern Indian Ocean during northern winter, which is attributed to the reduced BC mass fraction. [ABSTRACT FROM AUTHOR]