Shift in atmospheric rivers could affect Antarctic sea ice, glaciers

Science Daily  November 23, 2020 Researchers at UCLA investigated the atmospheric river (AR) frequency trends over the Southern Hemisphere using three reanalyses and two Community Earth System Model (CESM) ensembles. Their results show that AR frequency has been increasing over the Southern Ocean and decreasing over lower latitudes in the past four decades and that ARs have been shifting poleward. While the observed trends are mostly driven by the poleward shift of the westerly jet, the experiments indicate anthropogenic forcing would result in positive AR frequency trends over the Southern Ocean due mostly to moisture changes. They conclude that the […]

Artificial intelligence reveals hundreds of millions of trees in the Sahara

EurekAlert  October 20, 2020 A large proportion of dryland trees and shrubs grow in isolation, without canopy closure. These non-forest trees have a crucial role in biodiversity, and provide ecosystem services such as carbon storage, food resources and shelter for humans and animals. An international team of researchers (Denmark, USA – NASA Goddard Space Flight Center, Germany, France, Senegal, Belgium) mapped the crown size of each tree more than 3 m in size over a land area that spans 1.3 million km in the West African Sahara, Sahel and sub-humid zone. They detected over 1.8 billion individual trees. Although the […]

Volcanic ash may have a bigger impact on the climate than we thought

Science Daily  September 11, 2020 After the Mt. Kelut eruption in 2014 on the island of Java, stratospheric ash-rich aerosols were observed for months. A team of researchers in the US (University of Colorado, NOAA, industry) shows that the persistence of super-micron ash is consistent with a density near 0.5 g cm−3, close to pumice. Ash-rich particles dominate the volcanic cloud optical properties for the first 60 days. They found that the initial SO2 lifetime is determined by SO2 uptake on ash, rather than by reaction with OH as commonly assumed. About 43% more volcanic sulfur is removed from the stratosphere in […]

Developing models to predict storm surges

Science Daily  September 8, 2020 To develop the models researchers at the University of Central Florida linked large-scale climate variability events, such as El Niño, to variability in storm surge activity. They tested the models by having them predict past storm surge variability and compared their predictions with what actually occurred. The results indicated that the models matched the overall trends and variability of storm surge indicators for almost all coastal regions of the U.S during both the tropical and extra-tropical storm seasons. According to the researchers there is some capability in predicting storm surge variability over inter-annual to decadal […]

Atlantic hurricanes linked to weather system in East Asia

Science Daily  August 7, 2020 A team of researchers in the US (University of Iowa, Princeton University) has identified an association between the East Asian Subtropical Jet Stream (EASJ) during July–October and the frequency of Atlantic tropical cyclones during August–November based on observations for 1980–2018. According to the researchers the Rossby waves hitch a ride on the EASJ to the North Atlantic when tropical cyclones in the Atlantic are most likely to form. The waves affect wind shear, a key element in the formation of tropical storms. Rossby waves form within the Earth’s oceans and atmosphere because of the planet’s […]

Past evidence supports complete loss of Arctic sea-ice by 2035

Science Daily  August 10, 2020 Climate model simulations have previously failed to capture elevated temperatures, possibly because they were unable to correctly capture Last Interglacial (LIG) sea-ice changes. An international team of researchers (UK, Canada, USA- University of Washington) shows that the latest version of the fully coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. Improved model physics, including a sophisticated sea-ice melt-pond scheme, results in a complete simulated loss of Arctic sea ice in summer during the LIG, which has yet to be simulated in past generations of models. This […]

Agriculture – a climate villain? Maybe not!

Science Daily  July 7, 2020 The UN’s Intergovernmental Panel on Climate Change (IPCC) agriculture has affirmed that one of the main sources of greenhouse gases. According to the researchers in Sweden agriculture produces a significant amount of negative greenhouse gases, and it is important to reduce this in a sustainable manner. Carbon dioxide is caught by crops that, in turn, produce oxygen and at the same time binds carbon in roots and shoots. One part of this C transforms into soil organic C. But the main part transforms into harvested crops, that is, cereals like wheat and other carbohydrate products […]

Computing collaboration reveals global ripple effect of shifting monsoons

Phys.org  June 29, 2020 An international team of researchers (USA – Oak Ridge National Laboratory, UCLA, Mexico, Brazil, Italy, Hong Kong, Nigeria, Senegal, Rwanda, Pakistan) used an ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide an elaborate set of projections to date that illustrates possible futures for major monsoon regions. Each simulation covers the period from 1970 through 2100. They found that the weakening of latent heat driven atmospheric warming during the pre-monsoon period delays the overturning of atmospheric subsidence in the monsoon regions, which defers their transitioning into deep convective states. This causes […]

Warnings Issued as Unusually Thick Cloud of Saharan Dust Approaches The US

Science Alert  June 25, 2020 The dust cloud swept across the Atlantic from Africa over the past week, covering the Caribbean island of Puerto Rico since Sunday and hitting south Florida on Wednesday. Powered by strong winds, dust from the Sahara travels across the Atlantic Ocean from West Africa during the boreal spring. But the density of the current dust cloud over Cuba is well above normal levels. The dust clouds are loaded with minerals such as iron, calcium, phosphorous, silicon and mercury, and viruses, bacteria, fungi, pathogenic mites, staphylococci and organic pollutants…read more.

A Devastating US ‘Dust Bowl’ Is Twice as Likely Now Than During The Great Depression

Science Alert  May 19, 2020 During 1930s Dust Bowl drought across North America’s Great Plains caused widespread crop failures, large dust storms and considerable out-migration. This coincided with the central United States experiencing its hottest summers of the twentieth century in 1934 and 1936, with over 40 heatwave days and maximum temperatures surpassing 44 °C at some locations. According to an international team of researchers (Australia, UK, Sweden) heatwave activity in similarly rare events would be much larger under today’s atmospheric green house gas forcing the return period of a 1-in-100-year heatwave summer (as observed in 1936) would be reduced to […]