SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Meteorology

53

The oceans' phytoplankton that underpin the marine food chain appear to be changing in abundance due to global climate change. Here, we compare the first four years of data from a citizen science ocean transparency study, conducted by seafarers using home-made Secchi Disks and a free Smartphone application called Secchi, with contemporaneous satellite ocean colour measurements. Our results show seafarers collect useful Secchi Disk measurements of ocean transparency that could help future assessments of climate-induced changes in the phytoplankton when used to extend historical Secchi Disk data.

Concepts: Climate, Weather, Greek loanwords, Climate change, Meteorology, Ocean, Solar variation, Global warming

51

In countries where severe drought is an anticipated effect of climate change and in those that heavily depend on upstream nations for fresh water, the effect of drier conditions and consequent changes in the transboundary streamflow regime induced by anthropogenic interventions and disasters leads to uncertainty in regional water security. As a case in point, we analyze Jordan’s surface water resources and agricultural water demand through 2100, considering the combined impacts of climate change and land-use change driven by the Syrian conflict. We use bias-corrected regional climate simulations as input to high-resolution hydrologic models to assess three drought types: meteorological (rainfall decrease), agricultural (soil moisture deficit), and hydrologic (streamflow decline) under future scenarios. The historical baseline period (1981-2010) is compared to the future (2011-2100), divided into three 30-year periods. Comparing the baseline period to 2070-2100, average temperature increases by 4.5°C, rainfall decreases by 30%, and multiple drought-type occurrences increase from ~8 in 30 years to ~25 in 30 years. There is a significant increase in the contemporaneous occurrence of multiple drought types along with an 80% increase in simultaneous warm and dry events. Watershed simulations of future transboundary Yarmouk-Jordan River flow from Syria show that Jordan would receive 51 to 75% less Yarmouk water compared to historical flow. Recovery of Syrian irrigated agriculture to pre-conflict conditions would produce twice the decline in transboundary flow as that due to climate change. In Jordan, the confluence of limited water supply, future drought, and transboundary hydrologic impacts of land use severely challenges achieving freshwater sustainability.

Concepts: Agriculture, Water, Precipitation, Water management, Hydrology, Irrigation, Meteorology, Water resources

51

Analyses of (131)I, (137)Cs and (134)Cs in airborne aerosols were carried out in daily samples in Vilnius, Lithuania after the Fukushima accident during the period of March-April, 2011. The activity concentrations of (131)I and (137)Cs ranged from 12 μBq/m(3) and 1.4 μBq/m(3) to 3700 μBq/m(3) and 1040 μBq/m(3), respectively. The activity concentration of (239,240)Pu in one aerosol sample collected from 23 March to 15 April, 2011 was found to be 44.5 nBq/m(3). The two maxima found in radionuclide concentrations were related to complicated long-range air mass transport from Japan across the Pacific, the North America and the Atlantic Ocean to Central Europe as indicated by modelling. HYSPLIT backward trajectories and meteorological data were applied for interpretation of activity variations of measured radionuclides observed at the site of investigation. (7)Be and (212)Pb activity concentrations and their ratios were used as tracers of vertical transport of air masses. Fukushima data were compared with the data obtained during the Chernobyl accident and in the post Chernobyl period. The activity concentrations of (131)I and (137)Cs were found to be by 4 orders of magnitude lower as compared to the Chernobyl accident. The activity ratio of (134)Cs/(137)Cs was around 1 with small variations only. The activity ratio of (238)Pu/(239,240)Pu in the aerosol sample was 1.2, indicating a presence of the spent fuel of different origin than that of the Chernobyl accident.

Concepts: United States, Atlantic Ocean, Europe, Meteorology, Smoke, Radiation poisoning, Radioactive contamination, Financial ratio

48

A combination of climate events (e.g., low precipitation and high temperatures) may cause a significant impact on the ecosystem and society, although individual events involved may not be severe extremes themselves. Analyzing historical changes in concurrent climate extremes is critical to preparing for and mitigating the negative effects of climatic change and variability. This study focuses on the changes in concurrences of heatwaves and meteorological droughts from 1960 to 2010. Despite an apparent hiatus in rising temperature and no significant trend in droughts, we show a substantial increase in concurrent droughts and heatwaves across most parts of the United States, and a statistically significant shift in the distribution of concurrent extremes. Although commonly used trend analysis methods do not show any trend in concurrent droughts and heatwaves, a unique statistical approach discussed in this study exhibits a statistically significant change in the distribution of the data.

Concepts: Statistics, United States, Precipitation, Climate, Weather, Climate change, Meteorology, Analysis

46

The Intergovernmental Panel on Climate Change (IPCC) is an authoritative and influential source of reports on climate change. The lead authors of IPCC reports include scientists from around the world, but questions have been raised about the dominance of specific disciplines in the report and the disproportionate number of scholars from the Global North. In this paper, we analyze the as-yet-unexamined issue of gender and IPCC authorship, looking at changes in gender balance over time and analyzing women’s views about their experience and barriers to full participation, not only as women but also at the intersection of nationality, race, command of English, and discipline. Over time, we show that the proportion of female IPCC authors has seen a modest increase from less than 5% in 1990 to more than 20% in the most recent assessment reports. Based on responses from over 100 women IPCC authors, we find that many women report a positive experience in the way in which they are treated and in their ability to influence the report, although others report that some women were poorly represented and heard. We suggest that an intersectional lens is important: not all women experience the same obstacles: they face multiple and diverse barriers associated with social identifiers such as race, nationality, command of English, and disciplinary affiliation. The scientific community benefits from including all scientists, including women and those from the Global South. This paper documents barriers to participation and identifies opportunities to diversify climate science.

Concepts: Scientific method, Female, Science, Climate change, Meteorology, Intergovernmental Panel on Climate Change, Discipline, Women in science

46

The National Eclipse Weather Experiment (NEWEx) was a citizen science project designed to assess the effects of the 20 March 2015 partial solar eclipse on the weather over the United Kingdom (UK). NEWEx had two principal objectives: to provide a spatial network of meteorological observations across the UK to aid the investigation of eclipse-induced weather changes, and to develop a nationwide public engagement activity-based participation of citizen scientists. In total, NEWEx collected 15 606 observations of air temperature, cloudiness and wind speed and direction from 309 locations across the UK, over a 3 h window spanning the eclipse period. The headline results were processed in near real time, immediately published online, and featured in UK national press articles on the day of the eclipse. Here, we describe the technical development of NEWEx and how the observations provided by the citizen scientists were analysed. By comparing the results of the NEWEx analyses with results from other investigations of the same eclipse using different observational networks, including measurements from the University of Reading’s Atmospheric Observatory, we demonstrate that NEWEx provided a fair representation of the change in the UK meteorological conditions throughout the eclipse. Despite the simplicity of the approach adopted, robust reductions in both temperature and wind speed during the eclipse were observed.This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’.

Concepts: Earth, Sun, United Kingdom, Lunar eclipse, Meteorology, Wind, Eclipse, Solar eclipse

41

As climate change unfolds, weather systems in the United States have been shifting in patterns that vary across regions and seasons. Climate science research typically assesses these changes by examining individual weather indicators, such as temperature or precipitation, in isolation, and averaging their values across the spatial surface. As a result, little is known about population exposure to changes in weather and how people experience and evaluate these changes considered together. Here we show that in the United States from 1974 to 2013, the weather conditions experienced by the vast majority of the population improved. Using previous research on how weather affects local population growth to develop an index of people’s weather preferences, we find that 80% of Americans live in counties that are experiencing more pleasant weather than they did four decades ago. Virtually all Americans are now experiencing the much milder winters that they typically prefer, and these mild winters have not been offset by markedly more uncomfortable summers or other negative changes. Climate change models predict that this trend is temporary, however, because US summers will eventually warm more than winters. Under a scenario in which greenhouse gas emissions proceed at an unabated rate (Representative Concentration Pathway 8.5), we estimate that 88% of the US public will experience weather at the end of the century that is less preferable than weather in the recent past. Our results have implications for the public’s understanding of the climate change problem, which is shaped in part by experiences with local weather. Whereas weather patterns in recent decades have served as a poor source of motivation for Americans to demand a policy response to climate change, public concern may rise once people’s everyday experiences of climate change effects start to become less pleasant.

Concepts: United States, Climate, Weather, Climate change, Experience, Meteorology, Monsoon, Greenhouse gas

37

This study investigates the role of the eleven-year solar cycle on the Arctic climate during 1979-2016. It reveals that during those years, when the winter solar sunspot number (SSN) falls below 1.35 standard deviations (or mean value), the Arctic warming extends from the lower troposphere to high up in the upper stratosphere and vice versa when SSN is above. The warming in the atmospheric column reflects an easterly zonal wind anomaly consistent with warm air and positive geopotential height anomalies for years with minimum SSN and vice versa for the maximum. Despite the inherent limitations of statistical techniques, three different methods - Compositing, Multiple Linear Regression and Correlation - all point to a similar modulating influence of the sun on winter Arctic climate via the pathway of Arctic Oscillation. Presenting schematics, it discusses the mechanisms of how solar cycle variability influences the Arctic climate involving the stratospheric route. Compositing also detects an opposite solar signature on Eurasian snow-cover, which is a cooling during Minimum years, while warming in maximum. It is hypothesized that the reduction of ice in the Arctic and a growth in Eurasia, in recent winters, may in part, be a result of the current weaker solar cycle.

Concepts: Statistics, Sun, Standard deviation, Atmosphere, Meteorology, Stratosphere, Troposphere, Ozone layer

36

Accurate and timely surface precipitation measurements are crucial for water resources management, agriculture, weather prediction, climate research, as well as ground validation of satellite-based precipitation estimates. However, the majority of the land surface of the earth lacks such data, and in many parts of the world the density of surface precipitation gauging networks is even rapidly declining. This development can potentially be counteracted by using received signal level data from the enormous number of microwave links used worldwide in commercial cellular communication networks. Along such links, radio signals propagate from a transmitting antenna at one base station to a receiving antenna at another base station. Rain-induced attenuation and, subsequently, path-averaged rainfall intensity can be retrieved from the signal’s attenuation between transmitter and receiver. Here, we show how one such a network can be used to retrieve the space-time dynamics of rainfall for an entire country (The Netherlands, ∼35,500 km(2)), based on an unprecedented number of links (∼2,400) and a rainfall retrieval algorithm that can be applied in real time. This demonstrates the potential of such networks for real-time rainfall monitoring, in particular in those parts of the world where networks of dedicated ground-based rainfall sensors are often virtually absent.

Concepts: Water, Precipitation, Meteorology, Mobile phone, Radio, Cellular repeater, Broadcasting, Telecommunication

31

Clouds' efficiency at reflecting solar radiation and trapping the terrestrial radiation is strongly modulated by the diurnal cycle of clouds (DCC). Much attention has been paid to mean cloud properties due to their critical role in climate projections; however, less research has been devoted to the DCC. Here we quantify the mean, amplitude, and phase of the DCC in climate models and compare them with satellite observations and reanalysis data. While the mean appears to be reliable, the amplitude and phase of the DCC show marked inconsistencies, inducing overestimation of radiation in most climate models. In some models, DCC appears slightly shifted over the ocean, likely as a result of tuning and fortuitously compensating the large DCC errors over the land. While this model tuning does not seem to invalidate climate projections because of the limited DCC response to global warming, it may potentially increase the uncertainty of climate predictions.

Concepts: Scientific method, Earth, Precipitation, Weather, Climate change, Phase, Meteorology, Ocean