scholarly journals Changes in the Biomass of Vegetation in the Aral Sea Region

2021 ◽  
Vol 04 (05) ◽  
Author(s):  
B. А.Adilov ◽  
Keyword(s):  
Negative Correlation ◽  
Plant Biomass ◽  
Aral Sea ◽  
The Past ◽  
Long Term Changes ◽  
Ustyurt Plateau

Long-term changes in the plant biomass of the dried bottom of the Aral Sea and the Karakalpak part of the Ustyurt plateau were determined. Despite the drying of the Aral Sea 50 years ago, primary and intermediate stages of vegetation haloseries dominated by annual and shrub halophyte fraction remains as the main directing force of succession. The emergence and increase in the area of "zero" or arid local territories after the 1990s is observed in the central, especially southern part of the Karakalpak Ustyurt. In contrast to the formation of vegetation on the drained bottom of the Aral Sea, long-term changes in the biomass of various natural-territorial complexes of Ustyurt are characterized by a negative correlation with a reduction in the area of mirrors over the past 30 years.

scholarly journals Deducing Thickness Changes Of An Ice Sheet From Radio-Echo And Other Measurements

1975 ◽  
Vol 14 (70) ◽  
pp. 49-56 ◽  
Author(s):  
J. F. Nye ◽  
H. H. Wills
Keyword(s):  
Ice Sheet ◽  
Accumulation Rates ◽  
Short Term ◽  
The Past ◽  
Long Term Changes ◽  
Rate Of Accumulation

The displacement of the surface of an ice sheet and of markers set in its top layers can be measured geodetically, and also, it is expected, by radio-echo methods. The paper discusses how such measurements could be interpreted as showing long-term changes in the thickness of the ice sheet; in particular it discusses how one might design an experiment so as to avoid unwanted effects due to short-term changes in rate of accumulation. The analysis is similar to that of Federer and others (1970), but it corrects an error, so that when applied to their results for central Greenland it gives a different result for the lowering of the surface. Federer and others have already concluded that the average accumulation rates during the past 100 years have been below those needed to keep in balance with the velocity of the ice sheet as a whole. Using a particular model, it is found that this has resulted in the surface lowering at a mean rate of 0.050 m a−1 between 1871 and 1968, and a mean rate of 0.140 m a−1 between 1959 and 1968.

Long-term Changes of Waves at the German Baltic Sea Coast: Are There Trends from the Past?

2020 ◽  
Vol 95 (sp1) ◽  
pp. 1416
Author(s):  
Norman Dreier ◽  
Rain Männikus ◽  
Peter Fröhle
Keyword(s):  
Baltic Sea ◽  
The Past ◽  
Long Term Changes ◽  
Sea Coast

Quantifying and attributing changes in tropospheric ozone from a combination of satellite measurements and models

2020 ◽  
Author(s):  
Jessica Neu ◽  
Kazuyuki Miyazaki ◽  
Kevin Bowman ◽  
Gregory Osterman
Keyword(s):  
Time Series ◽  
Tropospheric Ozone ◽  
Earth Science ◽  
Satellite Measurements ◽  
Science Data ◽  
The Past ◽  
Long Term Changes ◽  
Earth Science Data

<p>Given the importance of tropospheric ozone as a greenhouse gas and a hazardous pollutant that impacts human health and ecosystems, it is critical to quantify and understand long-term changes in its abundance.  Satellite records are beginning to approach the length needed to assess variability and trends in tropospheric ozone, yet an intercomparison of time series from different instruments shows substantial differences in the net change in ozone over the past decade.  We discuss our efforts to produce Earth Science Data Records of tropospheric ozone and quantify uncertainties and biases in these records.  We also discuss the role of changes in the magnitude and distribution of precursor emissions and in downward transport of ozone from the stratosphere in determining tropospheric ozone abundances over the past 15 years.</p>

Long-Term Changes in the Living Arrangements of Children in the Netherlands

2009 ◽  
Vol 30 (5) ◽  
pp. 653-669 ◽  
Author(s):  
Ruben van Gaalen ◽  
Frans van Poppel
Keyword(s):  
World War Ii ◽  
The Netherlands ◽  
19Th Century ◽  
Living Arrangements ◽  
Data Sets ◽  
World War ◽  
The Past ◽  
Long Term Changes ◽  
The 19Th Century

The demographic and social processes of the past 150 years have radically changed the number of parents that children grow up with. This article uses two unique data sets to illustrate long-term changes in the living arrangements of children born between 1850 and 1985 in the Netherlands. Changes are described in terms of whether fathers, mothers, and stepparents lived with these children at birth and at age 15. A massive shift occurred in the living arrangements of the 1850-1879 cohort compared with the 1880-1899 cohort of children, and there is only a slight return to 19th-century conditions in the most recent birth cohort. Researchers and politicians should be careful when comparing contemporary family life with the extraordinary situation Western families were in just after World War II. To some degree, contemporary complexities are more comparable to those in the 19th century, although the sources of these complexities are different.

scholarly journals Unprecedented occurrence of snow disasters over the Qinghai-Tibetan Plateau since 1980

2021 ◽  
Vol 7 (4) ◽  
pp. 574-581
Author(s):  
Qi Liu ◽  
◽  
Le He ◽  
Jing Zeng ◽  
Yetang Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Natural Disasters ◽  
Animal Husbandry ◽  
Historical Records ◽  
The Past ◽  
Long Term Changes

<abstract> <p>Continuous snowfall caused natural disasters, called snow disasters here, frequently occur on the Qinghai-Tibetan Plateau of China in recent decades, and cause a large number of losses of animal husbandry and human property. However, their long-term changes are poorly known. Here we use historical records to place recent variations of snow disasters under the background of the past 200 years. There are 366 snow disasters events for the 1820–2009 period, of which 230 happen during 1980–2009. In particular, the count of each decadal events since 1980 is larger than any other time during the past two centuries.</p> </abstract>

scholarly journals Long-term changes in precipitation phase in Czechia

Geografie ◽  
2019 ◽  
Vol 124 (1) ◽  
pp. 41-55
Author(s):  
Martin Hynčica ◽  
Radan Huth
Keyword(s):  
Air Temperature ◽  
Daily Precipitation ◽  
Sharp Decrease ◽  
Total Precipitation ◽  
Solid Precipitation ◽  
The Past ◽  
Air Temperatures ◽  
Long Term Changes ◽  
Precipitation Phase

Long-term changes in precipitation phase are investigated at ten stations in Czechia. Trends are calculated from 1983 to 2018 for the period between November and April. Daily SYNOP reports and daily precipitation totals are used at every station, where number and occurrence of specific codes in SYNOP report determine daily precipitation totals as solid, combined (which represents, to a large extent, category of mixed precipitation), or liquid. Thereafter, it is possible to calculate trends of all precipitation phases as well as the proportion of solid to total precipitation (S/P; in %). The average S/P trend over all Czech stations is significantly negative (−0.60%·year-1) and accompanied by a sharp decrease in solid precipitation (−1.66 mm·year-1) and an increase in combined precipitation (1.50 mm·year-1). Thus, our results show a ship of precipitation phase from solid to combined. Because of the dependence of S/P on air temperature, we suppose that the current S/P decline is a manifestation of rising air temperatures in the past decades.

scholarly journals Farmers’ Perceptions of Climate Change, Long-term Variability and Trends in Rainfall in Apac District, Northern Uganda

2021 ◽  
Author(s):  
Francis Atube ◽  
Geoffrey M. Malinga ◽  
Martine Nyeko ◽  
Daniel M. Okello ◽  
Basil Mugonola ◽  
...  
Keyword(s):  
Climate Change ◽  
Abrupt Change ◽  
Smallholder Farmers ◽  
Change Points ◽  
Annual Rainfall ◽  
The Past ◽  
Rainfall Trends ◽  
Long Term Changes ◽  
Cropping Seasons

Abstract Background: Climate change poses a serious threat to agricultural livelihoods and food security of smallholder farmers in Sub Saharan Africa. Understanding long-term rainfall trends of variability and extremes at local scales and perceptions regarding long-term changes in climate variables is important in planning appropriate adaptation measures to climate change. This paper examines the perception of farmers in Apac district regarding long-term changes in climate variables and analyzes the trend of occurrence in seasonal and annual rainfall in Apac district, northern Uganda. A cross-sectional survey design was employed to collect data on perception of farmers regarding long-term changes in climate from 260 randomly selected small-holder farmers’ households across two sub-counties in Apac district by the administration of semi-structured questionnaires in February 2018. Monthly rainfall data sets from the Uganda Meteorological Authority (UMA) for the period 1980 to 2019 for the Apac district were also used to analyze trends of occurrences in seasonal and annual rainfall in the study area. The nonparametric Sequential Mann-Kendall (SMK) and Sequential SMK tests were employed at a 5% significance level to detect trends and abrupt change points in mean seasonal rainfall. Results: The majority of the respondents (87%) perceived a decrease in precipitation over the past 39 years. The plot of forward regression u(ti) values and backward regression u’(ti) values showed interactions indicating rainfall trends: rainfall lower and upper limits and abrupt change points in the different cropping seasons. Analysis of historical series of mean monthly and annual rainfall showed an abrupt change in rainfall in March, April, May (MAM) season in 1982. Although the September, October and November (SON) season did not show an abrupt significant change, there was a significant (p<0.05) increase in rainfall above the upper limit from 1994 to date. Conclusion: The mean seasonal rainfall for MAM and SON cropping seasons in the Apac district were highly variable from different time points within the past 39 years (1980-2019), while JJA did not realize a significant change in rainfall within the same study period. Thus, the two cropping seasons (MAM and SON) in the district experienced remarkable variations in rainfall. This, therefore, provides a basis for Government to strengthen the provision of an effective climate tailored agricultural advisory service to aid farmers’ adaptation planning at the local level and to assist smallholder farmers and land-use managers in developing effective adaptation management strategies to the effects of climate change.

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