Climatology and trend of cold waves over India during 1971-2010

Using Cold Wave (CW) information of 86 stations from Indian main land during the cold weather season (November to March) for the last 40 years (1971-2010), various statistical aspects of cold waves (CWs) and severe cold waves (SCWs) such as climatology and trend were examined. The link of CWs/SCWs with ENSO phases (La Nina & El Nino) was also examined. It was observed that many stations from north, northwest, east and central India together named as core CW zone (CCZ) experienced highest number of CW/SCW waves with relatively higher frequency during January. Noticeable decrease (increase) in the frequency and spatial coverage of CW/SCW days compared to their climatological values were observed during the El Nino (La Nina) years. There were significant decreasing trends in the CW/SCW days over most of the stations from CCZ. The total number of CW/SCW days/per decade over CCZ showed noticeable decrease during the recent decades 1991-2000 and 2001-2010, which coincided with the warmest decades for the country as well as for the globe. Associated with intense and persistent CW/SCW events, large human mortality were reported during some years of the study period.

Weather extremes : A spatio-temporal perspectives

Being mainly an agricultural country the economy of India and its growth mainly depends on the vagaries of the weather and in particular the extreme weather events. India with a land of unique climatic regime due to several characteristic features, including (i) two monsoon seasons (south-west and north-east) leading to drought & flood condition, active and break cycle of monsoon and also heavy rainfall leading to flash flood and landslides, (ii) two cyclone seasons (pre and post-monsoon cyclone seasons), (iii) hot weather season characterized by severe thunderstorms, dust storms and heat waves, (iv) cold weather season characterized by violent snow storms in the Himalayan regions, cold waves and fog. The socio-economic impacts of the extreme weather events such as floods, droughts, heavy rainfall, cyclones, hail storm, thunderstorm, heat and cold waves have been increasing due to large growth of population and urbanizations, which has led to greater vulnerability. A spatio-temporal analysis of these weather extremes over India will be very helpful to understand the vulnerability potential and to improve the forecast skill and use these forecasts in minimizing the adverse impacts of such weather extremes.

Magnitude, frequency, trends of heat and cold waves in recent decades and impact assessment in wheat: the case of north Bihar, India

The climatological distribution of heat and cold waves of two important agro-climatic zones zone-I (North Alluvial Plain), zone-II (North East Alluvial Plain) of the middle Indo-Gangetic Basin of Bihar state of India was analyzed. We used series of daily maximum and minimum temperature data from 1969-2015 of five stations. Results reveal that zone-I and zone-II experienced 248/184 and 275/199average number of heat and cold events, respectively. The trend analysis exhibited almost similar results for both the zones. The zone-I experienced on an average 4.22 and 7.22 heat and cold wave days per season (hot & cold weather period), respectively. There was a non-significant increasing trend @ +0.04/year for heat waves and significant decreasing trend for cold waves (-0.13/year). Zone-II on an average experienced 3 and 12 HW and CW events per season (hot and cold weather period), respectively. In this zone, heat waves were found to be increasing @ +0.11/year, whereas, significant decreasing trend was found for cold waves (+0.32/year). Study also revealed that, heat waves were more frequent and longer in June and May in zone-I and zone-II, respectively. Whereas, cold waves were more freq uent and longer in January for both the zones. These extreme events have profound impact on wheat crop if coincides with its critical stages. However, shifting planting dates and adoption of heat tolerant varieties may help in minimizing the negative impact of these extreme events.

Dust and sandstorm: ecosystem perspectives on dryland hazards in Northeast Asia: a review

Background A review of the literature was carried out to study dust and sandstorm (DSS) in terms of its ecosystem processes and relationship to other dryland disasters in Northeast Asia. Drylands are ecosystems that include grasslands, semi-deserts, and deserts, and these types of ecosystems are vulnerable due to their low primary productivity that depends on a small amount of precipitation. Results Drought, dust, desertification, and winter livestock disasters (called dzud) are unique natural disasters that affect the region. These disasters are related in that they share major causes, such as dryness and low vegetation cover that combine with other conditions, wind, cold waves, livestock, and land-surface energy, to dramatically impact the ecosystem. Conclusions The literature review in this study illustrates the macroscopic context of the spatial and temporal patterns of DSS according to geography, climate, and vegetation growth in the drylands of Northeast Asia. The effects of ocean climates and human activities were discussed to infer a possible teleconnection effect of DSS and its relations to desertification and dzud.

Health Risks to the Russian Population from Temperature Extremes at the Beginning of the XXI Century

Climate change and climate-sensitive disasters caused by climatic hazards have a significant and increasing direct and indirect impact on human health. Due to its vast area, complex geographical environment and various climatic conditions, Russia is one of the countries that suffers significantly from frequent climate hazards. This paper provides information about temperature extremities in Russia in the beginning of the 21st century, and their impact on human health. A literature search was conducted using the electronic databases Web of Science, Science Direct, Scopus, and e-Library, focusing on peer-reviewed journal articles published in English and in Russian from 2000 to 2021. The results are summarized in 16 studies, which are divided into location-based groups, including Moscow, Saint Petersburg and other large cities located in various climatic zones: in the Arctic, in Siberia and in the southern regions, in ultra-continental and monsoon climate. Heat waves in cities with a temperate continental climate lead to a significant increase in all-cause mortality than cold waves, compared with cities in other climatic zones. At the same time, in northern cities, in contrast to the southern regions and central Siberia, the influence of cold waves is more pronounced on mortality than heat waves. To adequately protect the population from the effects of temperature waves and to carry out preventive measures, it is necessary to know specific threshold values of air temperature in each city.

Geographical Analysis of Repeat Cold Waves in Kurdistan Region for the Period 2000-2017

In this paper, we investigated changes in cold waves in Kurdistan region over the period 2000–2017. Cold waves it means decrease 5oc minimum temperature degree at least from the average monthly minimum temperature for this month and continues for 3 days consecutive at least. The study found 132 cold waves repeat in Kurdistan region, that is 112 waves were the type of shortwave it means %84.85 of them were shortwaves, 18 waves medium and only 2 waves were the type of long waves. About severity of the temperature of cold waves the study also, found different types, for example in all cold waves about %67.42 or 89 waves were from the type of moderate waves, 30 waves strong and 13 waves were extreme. About of the cold days over the period of time include 904 threshold cold waves, in this number 530 days were in the type of the cold day of cold waves, and 374 days were the Temperature fluctuation of cold days. As well as the paper found that the annual repetition cold waves vary from month to month, and the season to season, it was found that cold waves were highest in spring and lowest in summer. The most geographical distribution of system atmospheric pressure effect on the weather and cold waves in study area is The Siberian Heights.