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). 
  • 321
  • 09 Feb 2021
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.
  • 316
  • 21 Aug 2020
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.
  • 291
  • 18 Nov 2021
Topic Review
UAVs to CBRN Threats monitoring
Unmanned aerial vehicles (UAVs) play an increasingly important role in various areas of life, including in terms of protection and security. The possibilities of using the devices were analyzed in terms of weather conditions, construction, and used materials in CBRN (chemical, biological, radiological, nuclear) threat situations. It was found that, thanks to the use of appropriate sensors, cameras, and software of UAVs integrated with a given system, it is possible to obtain information on air quality at a given moment, which is very important for the safety of people and the environment. However, several elements, including the possibility of use in acidification conditions, requires refinement to changing crisis conditions.
  • 288
  • 28 Dec 2020
Topic Review
Nanoparticle Number Concentration
The entry analyzes suspended particles number concentrations of 61 size fractions (184 nm to 17,165 nm) in the air at a traffic location. The average course of the individual fractions was analyzed at various intervals – daily, weekly, monthly and annually, in the period between 2017 and 2019. The data was then used to calculate the arithmetic mean for all the fractions (MS Excel, R) and then using a proprietary web application, heatmaps were constructed. The obtained results showed significant differences in both the annual and daily variation of number concentrations between the individual fractions differing in particle size. In the case of the annual variation, one can see a greater variability of smaller particles, which is most likely due to the source of the actual suspended particles. Meteorological and dispersion conditions are found as important factors for suspended particle concentrations. These can lead to significant differences from year to year. However, a comparison between 2018 and 2019 showed that even though the average absolute number concentrations can differ between years, the actual relative number concentrations, i.e. the ratios between the individual fractions remain very similar. In conclusion it can be said that the difference between the number concentration variation of the size fractions depends on both the actual pollution sources (especially in the long-term, i.e. the annual variation) and the actual size of the particles, which plays a role especially in the short-term (daily, weekly variation).
  • 266
  • 27 Oct 2020
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.
  • 263
  • 15 Apr 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.
  • 259
  • 22 Jan 2021
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.
  • 256
  • 28 Oct 2020
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.
  • 248
  • 09 Oct 2020
Topic Review Video
Global Solar Radiation
An empirical model of global solar irradiance (EMGSI) under all sky conditions was developed by using solar radiation and meteorological parameters at Sodankylä. The calculated hourly global solar irradiance is in agreement with that observed at the ground during 2008–2011 and at the top of the atmosphere (TOA). Using this empirical model, the albedos at the TOA and the surface were calculated, and they are in agreement with the satellite-retrieved values. 
  • 245
  • 25 Nov 2021
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