Terms Of Meteorological Parameters Research Articles

Long-term analysis of microseism during extreme weather events: Medicanes and common storms in the Mediterranean Sea

In this work, we analyze 12 meteorological events that occurred in the Mediterranean Sea during the period November 2011–November 2021 from a seismic point of view. In particular, we consider 8 Medicanes and 4 more common storms. Each of these events, in spite of the marked differences between them, caused heavy rainfall, strong wind gusts and violent storm surge with significant wave heights usually >3 m. We deal with the relationships between these meteorological events and the features of microseism (the most continuous and widespread seismic signal on Earth) in terms of spectral content, space-time variation of the amplitude and source locations tracked employing two different methods (amplitude decay-based grid search and array techniques). By comparing the positions of the microseism sources with the areas of significant storm surges, we observe that the microseism locations align with the actual locations of the storm surges for 10 out of 12 events analyzed (two Medicanes present very low intensity in terms of meteorological parameters and the microseism amplitude does not show significant variations during these two events). We also perform two analyses that allowed us to obtain both the seismic signature of these events, by using a method that exploits the coherence of continuous seismic noise, and their strength from a seismic point of view, called Microseism Reduced Amplitude. In addition, by integrating the results obtained from these two methods, we are able to “seismically” distinguish Medicanes and common storms. Consequently, we demonstrate the possibility of creating a novel monitoring system for Mediterranean meteorological events by incorporating microseism information alongside with other commonly employed techniques for studying meteorological phenomena. The integration of microseism with the data provided by routinely used techniques in sea state monitoring (e.g., wave buoy and HF radar) has the potential to offer valuable insights into the examination of historical extreme weather events within the context of climate change.

Mind The Gap: Towards and Beyond Impact Messaging to Enhance Tropical Cyclone Risk Communication

ABSTRACT Traditionally, meteorological agencies collect, analyse, and share technical information about natural hazards with emergency services organisations and community members; often sending different warning products to each of these groups. For the general public, effective risk communication requires that technical information be translated to first gain attention and build understanding of risk, and then continue to be exchanged by all parties. The World Meteorological Organization and its partner agencies have recognised this need for translated information by moving away from warnings describing risks solely in terms of meteorological parameters and towards clearer messaging emphasizing significance and potential impacts. While the move towards more relatable weather warning messaging is a positive one, risk communication is a complex, dynamic and interactive process that is highly dependent on audience psychology, knowledge, skills, and capabilities; presenting at once difficulties and opportunities for agencies. Over recent years, advertisers, politicians and public safety advocates have all improved their messaging through the use of big data, psychology, social networking and behavioural economics principles, yet the links between these elements and weather risk communication are still relatively immature. This report aims to build links between weather forecasters, social scientists and related industries by outlining three conceptual models social scientists have developed to meet different challenges in the field of risk communication; the mental models approach, risk information seeking and processing, and the protective action decision making model. Recent issues and successes in the communication of tropical cyclone risk will then be examined and compared to these models, and future opportunities will be discussed.

Tornado hazard for structural engineering

Tornado hazards have caused frequent and severe damages to built environment and lives. The severity of the hazards directly relates to the strength of the tornadic events in terms of meteorological parameters, as well as the resistance of buildings to the strong tornadic impacts. The tornado hazards are reviewed from both meteorological and engineering perspectives in this study. For each of the perspectives, current status of tornado hazard studies including the observation, monitoring, analysis, numerical and laboratory simulations, and limitations and future demands of development are discussed. While the two disciplines are fast advancing individually, their interaction and interdependence are deemed prominent and imperative in the future interdisciplinary studies.

Precipitation chemistry in western Japan: Its relationship to meteorological parameters

Precipitation chemistry at four sites along a longitudinal line in western Japan is discussed in terms of meteorological parameters. Wet-only samples were collected at Oki, Matsue, Kurahashi and Ashizuri along the line from north to south during April 1994–March 1999. The volume-weighted mean concentrations of nss-SO 4 2− showed a 12% decline and NO 3 − showed a 29% decline from north to south. For NH 4 + and nss-Ca 2+, stronger negative concentration gradients were found from north to south, and the opposite gradient held true for H +. The fractional acidity, [H +]/([nss-SO 4 2−]+[NO 3 −]), was lower at Oki and Matsue than at Kurahashi and Ashizuri. Monthly concentrations of these five ions showed a marked seasonal variation with a winter maximum and a summer minimum. In order to explore the relation between high concentration episodes of nss-SO 4 2− and NO 3 −, and air mass transport, back-trajectory analysis was applied to daily precipitation at the Oki and Ashizuri sites, the northernmost and southernmost of the four sites, respectively. For Oki, air masses for most of the episodic concentrations of the two ions were from the coastal areas of the Yellow Sea, the Bo Hay, and South Korea in winter. For Ashizuri, episodic air masses came from a wide region of the Asian Continent in the cold season, whereas no characteristic patterns were noted for warm-season trajectories. Sulfur emissions from a volcano located to the southwest of the Ashizuri site are also responsible for acidic nss-SO 4 2− episodes.

Statistical and diagnostic evaluation of a new-generation urban dispersion modelling system against an extensive dataset in the Helsinki area

We have developed a modelling system for predicting the traffic volumes, emissions from stationary and vehicular sources, and atmospheric dispersion of pollution in an urban area. This paper describes a comparison of the NO x and NO 2 concentrations predicted using this modelling system with the results of an urban air quality monitoring network. We performed a statistical analysis to determine the agreement between predicted and measured hourly time series of concentrations at four permanently located and three mobile monitoring stations in the Helsinki Metropolitan Area in 1996–1997 (at a total of ten urban and suburban measurement locations). At the stations considered, the so-called index of agreement values of the predicted and measured time series of the NO 2 concentrations vary between 0.65 and 0.82, while the fractional bias values range from −0.29 to +0.26. In comparison with corresponding results presented in the literature, the agreement between the measured and predicted datasets is good, as indicated by these statistical parameters. The seasonal variations of the NO 2 concentrations were analysed in terms of the relevant meteorological parameters. We also analysed the difference between model predictions and measured data diagnostically, in terms of meteorological parameters, including wind speed and direction (the latter separately for two wind speed classes), atmospheric stability and ambient temperature, at two monitoring stations in central Helsinki. The modelling system tends to overpredict the measured NO 2 concentrations both at the highest ( u⩾6 m s −1) and at the lowest wind speeds ( u<2 m s −1). For higher wind speeds, the modelling system overpredicts the measured NO 2 concentrations in certain wind direction intervals; specific ranges were found for both monitoring stations considered. The modelling system tends to underpredict the measured concentrations in convective atmospheric conditions, and overpredict in stable conditions. The possible physico-chemical reasons for these differences are discussed.

Evaluation of the CAR-FMI model against measurements near a major road

A field measurement campaign was conducted near a major road in southern Finland from September 15 to October 30, 1995. The concentrations of NO, NO2 and O3 were measured simultaneously at three locations, at three heights (3.5, 6 and 10m) on both sides of the road. Traffic densities and relevant meteorological parameters were also measured on-site. We have compared measured concentration data with the predictions of the road network dispersion model CAR-FMI, used in combination with a meteorological pre-processing model MPP-FMI. In comparison with corresponding results presented previously in the literature, the agreement of measured and predicted datasets was good, as measured using various statistical parameters. For all data (N=587), the index of agreement (IA) was 0.83, 0.82 and 0.89 for the measurements of NOx, NO2 and O3, respectively. The IA is a statistical measure of the correlation of the predicted and measured time series of concentrations. However, the modelling system overpredicts NOx concentrations with a fractional bias FB=+13%, and O3 concentrations with FB=+8%, while for NO2 concentrations FB=−2%. We also analyzed the difference between model predictions and measured data in terms of meteorological parameters. Model performance clearly deteriorated as the wind direction approached a direction parallel to the road, and for the lowest wind speeds. The range of variability concerning atmospheric stability, ambient temperature and the amount of solar radiation was modest during the measurement campaign. As expected, no clear dependencies of model performance were therefore detected in terms of these parameters. The experimental dataset is available for the evaluation of other roadside dispersion models.

Ozone and grosswetterlagen

Meteorological conditions have a decisive impact on surface ozone concentrations. In this study, an empirical model is used to explain the interdependence of ozone and grosswetterlagen. Different meteorological parameters such as air temperature, global solar radiation, relative humidity, wind direction and wind speed are used. Additional nitric oxide (NO) was taken as a representative for the emission situation and ozone maximum of the preceding day in order to evaluate the development of the photochemical situation.The dataset includes data collected over a period of three years (1992-1994) from three stations outside of Munich and one in the center of Munich.All values become variables by calculating means, sums or maxima of the basic dataset consisting of half-hour means. Seasonal periodicity of data is detected with Fourier analysis and eliminated by a division method after computing a seasonal index.The dataset is divided into three different grosswetterlagen groups, depending on main wind direction. One mostly cyclonic (westerly winds), one mixed (alternating winds) and one only anticyclonic (easterly winds). The last is completed with one summertime group including values from April to August.Factor analysis is performed for each group to obtain independent linear variable combinations. Overall, relative humidity is the dominant parameter, a typical value indicating meteorological conditions during a grosswetterlage.Linear multiple regression analysis is performed using the factors obtained to reveal how the ozone concentrations are explained in terms of meteorological parameters and NO. The results improve from cyclonic to anticyclonic grosswetterlagen in conformance with the increasing significance of photochemistry, indicated by the high solar radiation and high temperature, and the low relative humidity and low wind speed. The explained variance r(2) reaches its maximum with more than 50 % of the time in Munich center.This empirical model is applicable to the forecasting of local ozone maximum concentrations with a total standard error deviation of 8.5 to 12.8 % and, if ozone concentrations exceed 80 ppb, with a standard error deviation of 5.4 to 9.5 %.

Ozone and grosswetterlagen

Meteorological conditions have a decisive impact on surface ozone concentrations. In this study, an empirical model is used to explain the interdependence of ozone and grosswetterlagen. Different meteorological parameters such as air temperature, global solar radiation, relative humidity, wind direction and wind speed are used. Additional nitric oxide (NO) was taken as a representative for the emission situation and ozone maximum of the preceding day in order to evaluate the development of the photochemical situation. The dataset includes data collected over a period of three years (1992-1994) from three stations outside of Munich and one in the center of Munich.All values become variables by calculating means, sums or maxima of the basic dataset consisting of half-hour means. Seasonal periodicity of data is detected with Fourier analysis and eliminated by a division method after computing a seasonal index.The dataset is divided into three different grosswetterlagen groups, depending on main wind direction. One mostly cyclonic (westerly winds), onemixed (alternating winds) and one onlyanticyclonic (easterly winds). The last is completed with one summertime group including values from April to August.Factor analysis is performed for each group to obtain independent linear variable combinations. Overall, relative humidity is the dominant parameter, a typical value indicating meteorological conditions during a grosswetterlage.Linear multiple regression analysis is performed using the factors obtained to reveal how the ozone concentrations are explained in terms of meteorological parameters and NO. The results improve from cyclonic to anticyclonic grosswetterlagen in conformance with the increasing significance of photochemistry, indicated by the high solar radiation and high temperature, and the low relative humidity and low wind speed. The explained variance r(2) reaches its maximum with more than 50 % of the time in Munich center.This empirical model is applicable to the forecasting of local ozone maximum concentrations with a total standard error deviation of 8.5 to 12.8 % and, if ozone concentrations exceed 80 ppb, with a standard error deviation of 5.4 to 9.5 %.

Air mass characteristics in the vicinity oF Barrow, Alaska, 9–19 March 1983

The synoptic conditions over the Alaskan Arctic during the Arctic Gas and Aerosol Sampling Program (AGASP) of March 1983 are described. Air mass characteristics are pictured in terms of meteorological parameters, condensation nuclei, ozone and CO 2 concentrations, aerosol size and number distributions, and aerosol scattering coefficients, as measured at the Barrow Geophysical Monitoring for Climatic Change (GMCC) baseline station and by aircraft Latitude-altitude cross sections of meteorological and aerosol parameters indicated both strong vertical and horizontal variability within the Arctic air mass. Aerosol concentrations aloft were usually higher than those measured at the ground and peak-to-peak variations are greater aloft than at the surface, showing that the stable Arctic boundary layer reduces mixing from aloft to the surface. Thus, surface measurements cannot be extrapolated to higher levels in a straightforward manner. Horizontal variability in the haze, as determined by the aircraft, was found to be abrupt and was not generally due to the presence of strong meteorological fronts. During 9–19 March 1983, at least four different air mass types were present in the Barrow region, each of which was characterized by distinct meteorological, aerosol and trace gas characteristics.

Passive microwave atmospheric measurements - Part I : Absorption of microwaves by atmospheric gases-Oxygen and water vapour

The expression for absorption coefficient for microwave frequencies which is required in the inversion of radiative transfer equation is described in terms of meteorological parameters. Computational scheme has been developed and the results obtained for a standard tropical atmosphere for 19.35 GHz and 22.235 GHz, the frequencies used in satellite microwave radiometer onboard the second Indian satellite Bhaskara Relative contribution to the absorption coefficients for frequencies from 10 GHz to 70 GHz is also described for surface meteorological parameters. The algorithm and subroutine package may as well be used for interpreting any microwave radiometric data for meteorological and oceanographic studies.&#x0D;

An Integrated Approach to the Problem of Aircraft Icing

This paper is directed toward the need for a definition of the intensity of icing conditions in terms of meteorological parameters which the forecaster can predict, the manufacturer can design to, and the pilot can identify. Contradictions in present regulatory and meteorological definitions of icing conditions are discussed and a method of resolving them is suggested. A discussion of the FAR 25 icing envelopes as engineering rather than meteorological standards is presented. The question of whether a mean effective drop diameter is representative of the drop size spectrum within an icing cloud is considered. Definitions of icing intensity are suggested and a method of flight test data acquisition, allowing determination of the intensity of icing conditions encountered, is described.