Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

Changes in monsoon rainfall are caused by human-produced aerosols slowing the tropical atmospheric circulation. Observations show that South Asia underwent a widespread summertime drying during the second half of the 20th century, but it is unclear whether this trend was due to natural variations or human activities. We used a series of climate model experiments to investigate the South Asian monsoon response to natural and anthropogenic forcings. We find that the observed precipitation decrease can be attributed mainly to human-influenced aerosol emissions. The drying is a robust outcome of a slowdown of the tropical meridional overturning circulation, which compensates for the aerosol-induced energy imbalance between the Northern and Southern Hemispheres. These results provide compelling evidence of the prominent role of aerosols in shaping regional climate change over South Asia.

Anthropogenic aerosols and the weakening of the South Asian summer monsoon

Environmental perspective of COVID-19.

COVID-19's daily increasing cases and deaths have led to worldwide lockdown, quarantine and some restrictions. This study aims to analyze the effect of lockdown days on the spread of coronavirus in countries. COVID-19 cases and lockdown days data were collected for 49 countries that implemented the lockdown between certain dates (without interruption). The correlation tests were used for data analysis based on unconstrained (normal) and constrained (Tukey-lambda). The lockdown days was significantly correlated with COVID-19 pandemic based on unconstrained (r = -0.9126, F-ratio = 6.1654; t-ratio = 2.40; prob > .0203 with 49 observations) and based on Tukey-lambda (r = 0.7402, λ = 0.14). The lockdown, one of the social isolation restrictions, has been observed to prevent the COVID-19 pandemic, and showed that the spread of the virus can be significantly reduced by this preventive restriction in this study. This study offers initial evidence that the COVID-19 pandemic can be suppressed by a lockdown. The application of lockdown by governments is also thought to be effective on psychology, environment and economy besides having impact on Covid-19.

Is the lockdown important to prevent the COVID-19 pandemic? Effects on psychology, environment and economy-perspective.

The status, changes, and disturbances in geomorphological regimes can be regarded as controlling and regulating factors for biodiversity. Therefore, monitoring geomorphology at local, regional, and global scales is not only necessary to conserve geodiversity, but also to preserve biodiversity, as well as to improve biodiversity conservation and ecosystem management. Numerous remote sensing (RS) approaches and platforms have been used in the past to enable a cost-effective, increasingly freely available, comprehensive, repetitive, standardized, and objective monitoring of geomorphological characteristics and their traits. This contribution provides a state-of-the-art review for the RS-based monitoring of these characteristics and traits, by presenting examples of aeolian, fluvial, and coastal landforms. Different examples for monitoring geomorphology as a crucial discipline of geodiversity using RS are provided, discussing the implementation of RS technologies such as LiDAR, RADAR, as well as multi-spectral and hyperspectral sensor technologies. Furthermore, data products and RS technologies that could be used in the future for monitoring geomorphology are introduced. The use of spectral traits (ST) and spectral trait variation (STV) approaches with RS enable the status, changes, and disturbances of geomorphic diversity to be monitored. We focus on the requirements for future geomorphology monitoring specifically aimed at overcoming some key limitations of ecological modeling, namely: the implementation and linking of in-situ, close-range, air- and spaceborne RS technologies, geomorphic traits, and data science approaches as crucial components for a better understanding of the geomorphic impacts on complex ecosystems. This paper aims to impart multidimensional geomorphic information obtained by RS for improved utilization in biodiversity monitoring.

Linking the Remote Sensing of Geodiversity and Traits Relevant to Biodiversity—Part II: Geomorphology, Terrain and Surfaces

Effect of lockdown amid COVID-19 pandemic on air quality of the megacity Delhi, India.

Some respite for India's dirtiest river? Examining the Yamuna's water quality at Delhi during the COVID-19 lockdown period.

Long-term spatial and temporal trends of rainfall at monthly, seasonal, and annual scales have been studied for 12 meteorological stations of the Gangetic West Bengal located in Eastern India during 1901–2002 using 102 years of rainfall data. The non-parametric Mann-Kendall test and Sen’s slope estimator were used to detect trends and their slope. The changes are calculated in percentage over the time period. The results highlight a marked increase in post-monsoon (33.87%), the overall increase in annual (2.61%), a considerable decrease in winter (14.83%) as well as pre-monsoon (4.03%), and an inconsequential increase in monsoonal (1.21%) rainfall. In the annual and monsoonal series, the trend is positive in the southern half but negative in the northern counterpart. A considerable decrease in rainfall during June and August at most stations signifies that monsoon is losing in the early monsoonal months with an occurrence of mid-season dry spells. The increase in rainfall during September (13.80%) and October (34.38%) reveals that the monsoon is shifting toward these late monsoon and post-monsoon months, respectively. Both the decrease of rainfall in June (early monsoonal month), as well as an increase in rainfall in September (late monsoonal month) and October (start of post-monsoonal month), suggest that the monsoon is being delayed on its onset and withdrawal. In the Rarh region, monsoon rainfall is reducing whereas post-monsoon rainfall is increasing. In the Deltaic region, both monsoon and post-monsoon rainfalls are increasing. Such altering patterns of rainfall call for reviewing the agricultural practices and water use in this region.

Analysis of Rainfall Trends and its Spatial Patterns During the Last Century over the Gangetic West Bengal, Eastern India

Short-term exposure to ambient air quality of the most polluted Indian cities due to lockdown amid SARS-CoV-2.

In the contemporary era of global warming there is growing need to detail geographical variations of drought risk so as to investigate the impact of climate change in the densely populated agricultural tract of Gangetic West Bengal (GWB), eastern India. In aim to assess drought jeopardy at the regional scale, the present study deals with temporal trend and spatial pattern of drought during the last century over GWB. Standardized Precipitation Index (SPI) has been used to detail geographical variations of drought intensity, duration, frequency etc. at multiple time steps. Non-parametric Mann-Kendall test and Sen’s slope estimator are used to detect the trends and trends slope. In addition, the article focuses on developing a Composite Drought Risk Index (CDRI) integrating 10 parameters pertaining to drought exposure to detect which regions are most exposed to drought. The results portray a very diverse but consistent picture. The last century exhibits some consecutive deficit and surplus phases and after 1950s the extremity of surplus and deficit as well as drought duration have increased substantially. The impact of drought is expected to be rigorous at or adjacent areas of the western degraded plateau, particularly the northern Rarh and moribund delta where the drought intensities tend to increase while the rainfall as well as recurrence interval of drought tend to decrease. In a nutshell, this work provides evidences demonstrating the extension and intensification of aridity in the northern Rarh plain and Moribund delta. Such altered hydrolo-meteorological system hence calls for review of the agricultural practices and water use in GWB. The CDRI provides a means of obtaining a broad overview of drought risk and supposed to allow decision makers more in-depth investigation.

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Krishna Gopal Ghosh

Papers

Effect of lockdown amid COVID-19 pandemic on air quality of the megacity Delhi, India.

Some respite for India's dirtiest river? Examining the Yamuna's water quality at Delhi during the COVID-19 lockdown period.

Analysis of Rainfall Trends and its Spatial Patterns During the Last Century over the Gangetic West Bengal, Eastern India

Short-term exposure to ambient air quality of the most polluted Indian cities due to lockdown amid SARS-CoV-2.

Spatial and temporal appraisal of drought jeopardy over the Gangetic West Bengal, eastern India