Science Daily May 31, 2022 Analyses of global climate models consistently show that clouds constitute the biggest source of uncertainty and instability. But they occur on a length- and timescale that today’s models can’t come close to reproducing. Therefore, they included in models through a variety of approximations. A team of researchers in the US (UC Irvine, Lawrence Livermore National Laboratory, University of Washington, industry) is working to fix this glaring gap by breaking the climate modeling problem into two parts: a coarse-grained, lower-resolution (100km) planetary model and many small patches with 100 to 200 meter resolution. They developed a […]
Category Archives: Climatology
Release of two new datasets related to climate in Central Asia
Phys.org May 23, 2022 Researchers in China have derived a high-resolution (9 km) climate projection dataset over Central Asia (HCPD-CA) from dynamically downscaled results based on multiple bias-corrected global climate models. It contains four geostatic variables and 10 meteorological elements that are widely used to drive ecological and hydrological models. The reference and future periods are 1986–2005 and 2031–2050, respectively. The carbon emission scenario is Representative Concentration Pathway (RCP) 4.5. The evaluation showed that the data product has good quality in describing the climatology of all the elements in CA despite some systematic biases. Main features of projected climate changes over […]
Insights narrow the gap between large-scale atmospheric models and microscale features of atmospheric winds
Phys.org April 26, 2022 Modeling anomalies referred to as grey zone, arise when the model resolution approximates the length scale of turbulence features while modeling the atmosphere. An international team of researchers (USA – Notre Dame, Saudi Arabia) leveraged a new set of one-way nested, full-physics multiscale numerical experiments to quantify the magnitude of the errors introduced at gray zone resolutions in a real-case application. The new set of experiments conducted in Saudi Arabia spanned a wide range of scales and strategies to suppress resolved convection at gray zone resolutions. Detailed analyses of their experiments showed that (i) grid-dependent convective […]
Student’s research upends understanding of upper atmospheric wind
Phys.org November 10, 2021 Researchers at the University of Alaska analyzed ground-based remote sensing measurements of thermospheric neutral winds above Alaska, at 240 km altitude to study how space weather affects the well-known large-scale flow that carries winds from the sunlit dayside of the Earth across the polar cap into the night side. This flow feature is typically expected to emerge from the polar cap in the midnight sector and continue blowing equatorward well into sub-auroral latitudes. However, their data showed instances in which the equatorward flow instead stalls over Alaska in an unexpectedly abrupt manner. They found this most […]
Weather balloon data shows troposphere getting thicker, pushing tropopause higher over past 40 years
Phys.org November 8, 2021 Tropopause height (H) is a sensitive diagnostic for anthropogenic climate change. Previous studies showed increases in H over 1980–2000 but were inconsistent in projecting H trends after 2000. While H generally responds to temperature changes in the troposphere and stratosphere, the relative importance of these two contributions is uncertain. An international team of researchers (China, Canada, USA – NCAR, Boulder CO, Austria) used radiosonde balloon observations in the Northern Hemisphere (NH) over 20°N to 80°N to reveal a continuous rise of H over 1980–2020. Over 2001–2020, H increases at 50 to 60 m/decade, which is comparable […]
Earth’s orbit affects millennial climate variability
Phys.org November 2, 2021 The varying magnitude of millennial climate variability (MCV) was linked to orbitally paced glacial cycles over the past 800 kyr. The scarcity of a long-term integration of high-resolution continental and marine records hampers our understanding of the evolution and dynamics of MCV before the mid-Pleistocene transition. An international team of researchers (China, USA – Columbia University, Brown University, Switzerland, UK) has synthesized four centennial-resolved elemental time series, which they interpret as proxies for MCV, from North Atlantic, Iberian margin, Balkan Peninsula (Lake Ohrid) and Chinese Loess Plateau. The proxy records reveal that MCV was pervasive and persistent […]
Melting of polar ice shifting Earth itself, not just sea levels
Phys.org September 22, 2021 The loss of melting ice from land masses such as Greenland and Antarctica are causing the planet’s crust to warp slightly, even in spots more than 1,000 kilometres from the ice loss. A team of researchers in the US (Harvard University, Columbia University) analyzed satellite data on melt from 2003 to 2018 and studied changes in Earth’s crust to measure the shifting of the crust horizontally. They found that in some places the crust was moving more horizontally than it was lifting. They demonstrated that mass changes in the Greenland Ice Sheet and high latitude glacier […]
Scientists still don’t know how far melting in Antarctica will go, or the sea level rise it will unleash
Phys.org September 21, 2021 Ice loss from the Antarctic and Greenland ice sheets was the largest contributor to sea level rise in recent decades. Adapting to the projected sea level rise that will have widespread effects in Australia and around the world due to ice sheet melt are so wide that developing ways for societies to adapt will be incredibly expensive and difficult. An international scientific collaboration known as the Ice Sheet Model Intercomparison Project (ISMIP6) is quantifying how much Antarctic ice sheets will contribute to sea level rise has identified basal melt, the melting of ice shelves from underneath, […]
Jet stream changes could amplify weather extremes by 2060s
Phys.org September 13, 2021 A team of researchers in the US (MIT, Woods Hole Oceanographic Institution, University of Arizona, University of Hawaii, Desert Research Institute) collected glacial ice core samples from nearly 50 sites spanning the Greenland ice sheet to reconstruct changes in windiness across the North Atlantic dating back to the eighth century. Model projections forecast a northward migration of the North Atlantic jet stream which could render the jet stream significantly different within a matter of decades. The ice core layers tell us about how much precipitation fell each year and about the temperatures that airmasses were exposed […]
Scientists solve mystery of icy plumes that may foretell deadly supercell storms
Science Daily September 9, 2021 The strongest supercell thunderstorms typically feature an above-anvil cirrus plume (AACP), which is a plume of ice and water vapor in the lower stratosphere that occurs downwind of the ambient stratospheric flow in the lee of overshooting deep convection. AACP-origin hydration of the stratosphere has a poorly constrained role in ozone destruction and surface warming. A team of researchers in the US (Stanford University, University of Wisconsin) used large eddy simulations corroborated by radar observations to understand the physics of AACP generation. They showed that the overshooting top of a simulated supercell can act as […]