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Topic Review
Wind Farms and Humidity
Several investigations have shown that enhanced mixing brought about by wind turbines alters near-surface meteorological conditions within and downstream of a wind farm. When scalar meteorological parameters have been considered, the focus has most often centered on temperature changes. A subset of these works has also considered humidity to various extents. These limited investigations are complemented by just a few studies dedicated to analyzing humidity changes. With onshore wind turbines often sited in agricultural areas, any changes to the microclimate surrounding a turbine can impact plant health and the length of the growing season; any changes to the environment around an offshore wind farm can change cloud and fog formation and dissipation, among other impacts. This article provides a review of observational field campaigns and numerical investigations examining changes to humidity within wind turbine array boundary layers. Across the range of empirical observations and numerical simulations, changes to humidity were observed in stably stratified conditions. In addition to the role of atmospheric stability, this review reveals that the nature of the change depends on the upstream moisture profile; robustness of the mixing; turbine array layout; distance from the turbine, in all three directions; and vertical temperature profile.
  • 1.2K
  • 15 Apr 2022
Topic Review
Air Pollution Policy in Israel
Since its establishment in 1948, the State of Israel has been oriented towards economic development and industrialization, with a transportation sector increasingly focused on private cars. In 1961, initial awareness of environmental risks led to the adoption of the Abatement of Nuisances Law, which served as the platform for air pollution policy for several decades, even as population growth and growth of the industrial sector, including fossil fuel power plants, led to a continuous increase in air pollution. In the early 2000s, the environmental movement in Israel criticized local air pollution policy as being out of date and started to promote a new Clean Air Law. The law, which was adopted in 2008 and came into force in 2011, was a watershed in air pollution policy in Israel. It includes ambient air quality values for 28 contaminants, emission permits for the industrial sector based on best available techniques (BAT), an enforcement system, and a unified and transparent monitoring system. This entry introduces the history of air pollution policy in Israel from 1948, through the 1961 and 2008 landmark legislations and their strengths and weaknesses, to the present. Also, it gives  recommendations for future air pollution policy in Israel.
  • 1.2K
  • 28 Oct 2020
Topic Review
Convective Boundary Layer
The Convective Boundary layer (CBL), also known as the daytime Planetary boundary layer, is the part of the atmosphere most directly affected by solar heating of the earth's surface. This layer extends from the earth surface to a capping inversion that typically locates at a height of 1–2 km by midafternoon over land. Below the capping inversion (10-60% of CBL depth, also called entrainment zone in the daytime), CBL is divided into two sub-layers: mixed layer (35-80% of CBL depth) and surface layer (5-10% of CBL depth). The mixed layer, the major part of CBL, has a nearly constant distribution of quantities such as potential temperature, wind speed, moisture and pollutant concentration because of strong buoyancy generated convective turbulent mixing. Parameterization of turbulent transport is used to simulate the vertical profiles and temporal variation of quantities of interest, because of the randomness and the unknown physics of turbulence. However, turbulence in the mixed layer is not completely random, but is often organized into identifiable structures such as thermals and plumes in the CBL. Simulation of these large eddies is quite different from simulation of smaller eddies generated by local shears in the surface layer. Non-local property of the large eddies should be accounted for in the parameterization.
  • 1.2K
  • 24 Nov 2022
Topic Review Video Peer Reviewed
Lorenz’s View on the Predictability Limit of the Atmosphere
To determine whether (or not) the intrinsic predictability limit of the atmosphere is two weeks and whether (or not) Lorenz’s approaches support this limit, this entry discusses the following topics: (A). The Lorenz 1963 model qualitatively revealed the essence of a finite predictability within a chaotic system such as the atmosphere. However, the Lorenz 1963 model did not determine a precise limit for atmospheric predictability. (B). In the 1960s, using real-world models, the two-week predictability limit was originally estimated based on a doubling time of five days. The finding was documented by Charney et al. in 1966 and has become a consensus. Throughout this entry, Major Point A and B are used as respective references for these topics. A literature review and an analysis suggested that the Lorenz 1963 model qualitatively revealed a finite predictability, and that findings of the Lorenz 1969 model with a saturation assumption supported the idea of the two-week predictability limit, which, in the 1960s, was estimated based on a doubling time of five days obtained using real-world models. However, the theoretical Lorenz 1963 and 1969 models have limitations, such as a lack of certain processes and assumptions, and, therefore, cannot represent an intrinsic predictability limit of the atmosphere. This entry suggests an optimistic view for searching for a predictability limit using different approaches and is supported by recent promising simulations that go beyond two weeks.
  • 1.1K
  • 07 Aug 2023
Topic Review
Water-Soluble Organic Matter
Inspired by studies on outdoor organic aerosols (OA), recent studies discusses and prioritizes issues related to indoor water-soluble OA and their effects on human health, providing a basis for future research in the field. The following three main topics are addressed: (1) what is known about the origin, mass contribution, and health effects of water-soluble organic matter (WSOM) in outdoor air particles; (2) the current state-of-the-art on the WSOM in indoor air particles, the main challenges and opportunities for its chemical characterization and cytotoxicity evaluation; and (3) why the aerosol WSOM should be considered in future indoor air quality studies.
  • 1.1K
  • 08 Nov 2021
Topic Review
Wind Speed Analysis of Hurricane Sandy
The database of the HWind project sponsored by the National Oceanic and Atmospheric Administration (NOAA) for hurricanes between 1994 and 2013 is analysed. Moreover, the wind speed of Hurricane Sandy is studied.
  • 1.1K
  • 18 Nov 2021
Topic Review Video
Coexisting Attractors within Classical and Generalized Lorenz Models
An in-depth analysis of classical Lorenz models and newly developed, generalized Lorenz models suggested a revised view that “the entirety of weather possesses a dual nature of chaos and order with distinct predictability”, in contrast to the conventional view of “weather is chaotic”.  Major features that yield distinct predictability include three types of solutions (for monostability), two kinds of attractor coexistence (for multistability), and their concurrent and alternative appearance.  The distinct predictability suggests limited predictability for chaotic solutions and unlimited predictability (or up to their lifetime) for non-chaotic solutions. Here, the following features are discussed: (1) an analogy for monostability and multistability using skiing vs. kayaking; (2) single-types of attractors, SDIC, and monostability within the Lorenz 1963 (L63) model; (3) coexisting attractors and multistability within the generalized Lorenz model (GLM); (4) time varying multistability and slow time-varying solutions; and (5) the onset of emerging solutions.
  • 1.1K
  • 29 Nov 2022
Topic Review
Climate Change and Society
Society is at an important intersection in dealing with the challenges of climate change, while the natural sciences are insufficient to deal with these challenges. Critical aspects of sociological perspectives related to climate change research are brought together in this review in the hope of fostering greater interdisciplinary collaboration between the natural and social sciences.
  • 1.1K
  • 22 Jan 2021
Topic Review
Climate Change and Water Resources
Water resources are highly dependent on climatic variations. The quantification of climate change impacts on surface water availability is critical for agriculture production and flood management. The current study focuses on the projected streamflow variations in the transboundary Mangla Dam watershed. Precipitation and temperature changes combined with future water assessment in the watershed are projected by applying multiple downscaling techniques for three periods (2021–2039, 2040–2069, and 2070–2099). Streamflows are simulated by using the Soil and Water Assessment Tool (SWAT) for the outputs of five global circulation models (GCMs) and their ensembles under two representative concentration pathways (RCPs). Spatial and temporal changes in defined future flow indexes, such as base streamflow, average flow, and high streamflow have been investigated in this study. Results depicted an overall increase in average annual flows under RCP 4.5 and RCP 8.5 up until 2099. The maximum values of low flow, median flow, and high flows under RCP 4.5 were found to be 55.96 m3/s, 856.94 m3/s, and 7506.2 m3/s and under RCP 8.5, 63.29 m3/s, 945.26 m3/s, 7569.8 m3/s, respectively, for these ensembles GCMs till 2099. Under RCP 4.5, the maximum increases in maximum temperature (Tmax), minimum temperature (Tmin), precipitation (Pr), and average annual streamflow were estimated as 5.3 °C, 2.0 °C, 128.4%, and 155.52%, respectively, up until 2099. In the case of RCP 8.5, the maximum increase in these hydro-metrological variables was up to 8.9 °C, 8.2 °C, 180.3%, and 181.56%, respectively, up until 2099. The increases in Tmax, Tmin, and Pr using ensemble GCMs under RCP 4.5 were found to be 1.95 °C, 1.68 °C and 93.28% (2021–2039), 1.84 °C, 1.34 °C, and 75.88%(2040–2069), 1.57 °C, 1.27 °C and 72.7% (2070–2099), respectively. Under RCP 8.5, the projected increases in Tmax, Tmin, and Pr using ensemble GCMs were found as 2.26 °C, 2.23 °C and 78.65% (2021–2039), 2.73 °C, 2.53 °C, and 83.79% (2040–2069), 2.80 °C, 2.63 °C and 67.89% (2070–2099), respectively. Three seasons (spring, winter, and autumn) showed a remarkable increase in streamflow, while the summer season showed a decrease in inflows. Based on modeling results, it is expected that the Mangla Watershed will experience more frequent extreme flow events in the future, due to climate change. These results indicate that the study of climate change's impact on the water resources under a suitable downscaling technique is imperative for proper planning and management of the water resources.
  • 1.1K
  • 23 Oct 2020
Topic Review
Range (Aeronautics)
The maximal total range is the maximum distance an aircraft can fly between takeoff and landing. Powered aircraft range is limited by the aviation fuel energy storage capacity (chemical or electrical) considering both weight and volume limits. Unpowered aircraft range depends on factors such as cross-country speed and environmental conditions. The range can be seen as the cross-country ground speed multiplied by the maximum time in the air. The fuel time limit for powered aircraft is fixed by the available fuel (considering reserve fuel requirements) and rate of consumption. Some aircraft can gain energy while airborne through the environment (e.g. collecting solar energy or through rising air currents from mechanical or thermal lifting) or from in-flight refueling. These aircraft could theoretically have infinite range. Ferry range means the maximum range that a aircraft engaged in ferry flying can achieve. This usually means maximum fuel load, optionally with extra fuel tanks and minimum equipment. It refers to transport of aircraft without any passengers or cargo. Combat radius is a related measure based on the maximum distance a warplane can travel from its base of operations, accomplish some objective, and return to its original airfield with minimal reserves.
  • 1.1K
  • 18 Oct 2022
Topic Review
Tungurahua Volcano (Ecuador)
Since April of 2015, the ash dispersion and ash fallout due to Vulcanian eruptions at Tungurahua, one of the most active volcanoes in Ecuador, have been forecasted daily. For this purpose, our forecasting system uses the meteorological Weather Research and Forecasting (WRF) and the FALL3D models. Previously, and based on field data, laboratory, and numerical studies, corresponding eruption source parameters (ESP) have been defined. We analyzed the historically forecasted results of the ash fallout quantities over four years (April 2015 to March 2019), in order to obtain the average isomass and probability maps for three-month periods: February–March–April (FMA), May–June–July (MJJ), August–September–October (ASO), and November–December–January (NDJ). Our results indicate similar ash fallout shapes during MJJ and ASO, with a clear and defined tendency toward the west of the volcano; this tendency is less defined during NDJ and FMA. The proximal region west of the volcano (about 100 km to the west) has the highest probability (>70%) of being affected by ash fallout. The distant region to the west (more than 100 km west) presented low to medium probabilities (10%–70%) of ash fallout. The cities of Guaranda (W, 60% to 90%), Riobamba (SW, 70%), and Ambato (NW, 50% to 60%) have the highest probabilities of being affected by ash fallout. Among the large Ecuadorian cities, Guayaquil (SW, 10% to 30%) has low probability, and Quito (N, ≤5%) and Cuenca (SSE, <5%) have very low probabilities of being affected by ash fallout. High ash clouds can move in different directions, compared to wind transport near the surface. Therefore, it is possible to detect ash clouds by remote sensing which, in Ecuador, is limited to the layers over the meteorological clouds, which move in a different direction than low wind; the latter produces ash fallout over regions in different directions compared to the detected ash clouds. In addition to the isomass/probability maps and detected ash clouds, forecasting is permanently required in Ecuador.
  • 1.1K
  • 21 Aug 2020
Topic Review
Air during New Year’s Eve
Mosses are one of the best bioindicators in the assessment of atmospheric aerosol pollution by heavy metals. Studies using mosses allow both short- and long-term air quality monitoring. The increasing contamination of the environment (including air) is causing a search for new, cheap and effective methods of monitoring its condition. Once such method is the use of mosses in active biomonitoring. The aim of the entry was to assess the atmospheric aerosol pollution with selected heavy metals (Ni, Cu, Zn, Cd, Hg and Pb) from the smoke of fireworks used during New Year’s Eve in the years 2019/2020 and 2020/2021.
  • 1.1K
  • 16 Aug 2021
Topic Review
Comparison between IRI and IRTAM
This paper focuses on a detailed comparison, based on the F2-layer peak characteristics foF2 and hmF2, between the International Reference Ionosphere (IRI), which is a climatological empirical model of the terrestrial ionosphere, and the IRI Real-Time Assimilative Mapping (IRTAM) procedure, which is a real-time version of IRI based on data assimilation from a global network of ionosondes. 
  • 1.0K
  • 11 Aug 2021
Topic Review
Near-Surface Wind
Near-surface wind is one of the most important meteorological parameters. Near-surface wind grid products are an important part of live analysis products . Reliable near-surface wind products have an important role in the monitoring, prediction, and study of wind disasters. The evaluation of near-surface wind products can provide the direction for improving the data quality for Hainan, provide basic support for fine-grid forecasting and meteorological services, and help to reduce the losses that are caused by wind disasters.
  • 1.0K
  • 09 Jul 2021
Topic Review
NASA Micropulse Lidar Rain Algorithm
Precipitation modifies atmospheric column thermodynamics through the process of evaporation and serves as a proxy for latent heat modulation. For this reason, a correct precipitation parameterization (especially for low-intensity precipitation) within global scale models is crucial. In addition to improving our modeling of the hydrological cycle, this will reduce the associated uncertainty of global climate models in correctly forecasting future scenarios, and will enable the application of mitigation strategies. In this study we present a proof of concept algorithm to automatically detect precipitation from lidar measurements obtained from the National Aeronautics and Space Administration Micropulse lidar network (MPLNET). 
  • 975
  • 09 Feb 2021
Topic Review
Climate Causal Flows
Physical processes govern climate at different spatial and temporal scales. These physical processes themselves constitute the transfer or flow of energy and mass. Causality methods have been used in recent years to study the flow of energy and mass. These methods give an indication of the direction of the flow and the intensity of the transfer. Climatic causal flows refer to hypotheses about physical processes that have been discovered using causal inference methods.
  • 921
  • 27 Jan 2022
Topic Review
Wildfire Spread Risk Challenge
Wildfires are sudden and destructive natural hazards that pose significant challenges in response and relief efforts. Wildfires occur annually across the globe, influenced by factors such as climate, combustible materials, and ignition sources. In recent years, researchers have shown increasing interest in studying wildfires, resulting in a large number of related studies. These studies cover a variety of topics including wildfire forecasting and forecasting, spatial and temporal pattern analysis, ecological impact assessment, simulation of wildfire behavior, identification of contributing factors, development of risk assessment models, management techniques for combustible materials, firefighting decision-making techniques, and fire protection. burning method. Understanding the factors that influence wildfire spread behavior, employing modeling methods, and conducting risk assessments are critical for effective wildfire prevention, mitigation, and emergency response.
  • 911
  • 16 Jun 2023
Topic Review
Air Quality Management
Most of the Ecuador buses run on diesel, emitting high quantities  NOx and PM2.5.  Into the framework of promoting the use of low impact energy and efficiency, the Ecuadorian energy efficiency law requires by 2025 that all vehicles incorporated into the public transportation system must be electric. To assess the effects on the air quality of Cuenca, a city located al the Southern Andean region of Ecuador, we used the Eulerian Weather Research and Forecasting with Chemistry (WRF-Chem) model. The results were consistent with the pollutants' trends observed during the COVID-19 lockdown in this city.
  • 903
  • 09 Oct 2020
Topic Review
Local Strong Sandstorms
The local strong sandstorms (LSS), similar to haboobs in Sahara and the North America, often occur suddenly, in tens of minutes during the late afternoon, and before dusk in deserts in China, causing a significant impact on the local atmospheric environment. The Sudan haboob or American haboob often appears in the wet season, followed by thunderstorm events. In contrast, the LSS in China appears most frequently in relatively dry season. The lack of observational data in weather conditions before their formation, during their development and after their disappearance have hindered our understanding of the evolution mechanism of LSS/haboobs.
  • 872
  • 17 Jun 2021
Topic Review Peer Reviewed
Revisiting Lorenz’s Error Growth Models: Insights and Applications
This entry examines Lorenz’s error growth models with quadratic and cubic hypotheses, highlighting their mathematical connections to the non-dissipative Lorenz 1963 model. The quadratic error growth model is the logistic ordinary differential equation (ODE) with a quadratic nonlinear term, while the cubic model is derived by replacing the quadratic term with a cubic one. A variable transformation shows that the cubic model can be converted to the same form as the logistic ODE. The relationship between the continuous logistic ODE and its discrete version, the logistic map, illustrates chaotic behaviors, demonstrating computational chaos with large time steps. A variant of the logistic ODE is proposed to show how finite predictability horizons can be determined, emphasizing the continuous dependence on initial conditions (CDIC) related to stable and unstable asymptotic values. This review also presents the mathematical relationship between the logistic ODE and the non-dissipative Lorenz 1963 model.
  • 871
  • 15 Jul 2024
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