Hasil untuk "Meteorology. Climatology"

C. Frei, C. Schär

Chu Qiu, Jinhui Cai, Zheng Wang et al.

Abstract Ionograms are radar echo graphs that depict vertical ionospheric density profiles, structures, fluctuations, and irregularities, with the F region represented by F‐trace and Spread‐F features in the graphs. In this paper, IonoGAN, an enhanced neural network based on the Generative Adversarial Network architecture, is proposed for direct prediction of ionograms and the variation of these ionospheric conditions. This estimation is based on the trends of density profiles and the waves/structures presented in the ionogram sequence. The IonoGAN extends the spatiotemporal information‐preserving and perception‐augmented (STIP) ability by incorporating a Local‐Global discriminator to focus on the F region in ionograms. In addition, two scientific characteristics of ionospheric natural phenomena are extracted and used as constraints in the modeling: Spread‐F Classification Accuracy (SFCA) and Absolute Value of the Correlation Coefficient for the F trace (AVCC‐F). For training, ionograms from Hainan Fuke station (19.5°N, 109.1°E, magnetic 11°N) during 2002–2015 were processed into 36,435 sequences with Spread‐F phenomena and 147,147 sequences without. To strengthen their features, Spread‐F phenomena were further classified into types of frequency, range, mix, and strong range. After the parameter training, the IonoGAN achieved SFCA and AVCC‐F converging to their optimal values: on the 2016 test set, SFCA = 90.92%, AVCC‐F = 0.6917. This modification enables the network to effectively capture the distinct features of the ionospheric F trace and the Spread‐F phenomenon during both quiet and disturbed periods.

Nicholas S. Novella, W. Thiaw

Roger Street, Torsten Weber

R. A. Viscarra Rossel, M. Zhang, T. Behrens et al.

Abstract Understanding the change in soil organic carbon (C) stock in a warmer climate and the effect of current land management on that stock is critical for soil and environmental conservation and climate policy. By simulation modeling, we predicted changes in Australia’s soil organic C stock from 2010 to 2100. These vary from losses of 0.014–0.077 t C ha−1 year−1 between 2020 and 2045 and 0.013–0.047 t C ha−1 year−1 between 2070 and 2100, under increasing emissions of greenhouse gases and temperature. Thus, Australian soil will be a net emitter of CO2. Depending on the future socio-economic conditions, we predict that croplands will accrue as much as 0.19 t C ha−1 year−1 between 2020 and 2045 due to their management, but accrual will decrease with warming and increased emissions by 2070–2100. The gains will be too small to counteract the losses of C from the larger areas of rangelands and coastal regions that are more sensitive to a warmer climate. In principle, prudent management of the rangelands, for example, improving grazing management and regenerating biodiverse, endemic native plant communities, could sequester more C and mitigate the loss; in practice, it may be more difficult, requiring innovation, interdisciplinary science, cultural awareness and effective policies.

Jana Foxe, Nives Dolšak, Aseem Prakash

Is the UK public willing to financially support environmental organizations that adopt disruptive tactics (museum and art gallery protests, sporting event disruptions, and traffic stoppages), as opposed to orthodox tactics (litigation, lobbying, and research and education)? Using a conjoint choice experiment (N = 1,023; N _obs = 10,230), we asked respondents’ willingness to donate £25 to hypothetical environmental organizations that differ in terms of (1) advocacy tactics, (2) expenditure on administrative overheads, (3) representation of women on their boards, (4) organizational age, (5) organizational size, (6) number of volunteers, and (7) revenue from citizen donations. We find respondents’ willingness to donate diminishes when organizations adopt disruptive tactics. These results hold across party preferences, ideology, generation, location, and environmental policy attitudes. Further, respondents are willing to donate to organizations that rely on donations from the general public, have low overheads, are supported by volunteer labor, and provide representation to women on their boards.

Maryam Kamali, Masoud Torabi Azad

Precipitation is an important but variable quantity in the climate system. Monitoring the changes of this quantity has many complications, so in this research, we tried to investigate the trend of precipitation changes in the coastal strip of southern Iran using ERA5 data. In this regard, the monthly rainfall data of ERA5 model was used for the time period of 1981-2020. For this investigation, linear regression tests and Mann-Kendall test were used to measure the correlation and the trend of changes of this quantity in 3 provinces of Khuzestan, Bushehr and Hormozgan. Examining the results of the correlation between the observational data and the model data indicated a high and significant correlation, which showed a high correlation of 95 percent with a correlation coefficient of more than 0.92. Examining the time series of the data indicated an increase in regional rainfall in the spring season and a decrease in the winter season.Intra-seasonal changes showed that winter rains decreased compared to autumn rains, spring rains increased compared to autumn, summer rains increased compared to autumn rains, and summer rains increased compared to spring rains in the region. . The monthly survey of rainfall showed that the concentration of the increasing rate of rainfall was concentrated in the northern regions of Khuzestan province, which shows a significant upward trend in some regions such as the east of Hormozgan province in January.

Lanabere Vanina, Dimmock Andrew P., Rosenqvist Lisa et al.

Historically, Sweden has reported several impacts on transformers and transmission lines related to geomagnetically induced currents (GICs) that develop during strong space weather events. GICs are driven by the geoelectric field (E), and their intensity depends on various factors, including the lithology conductivity and the rate of change of the Earth’s magnetic field. The purpose of this study is to perform an extreme value (EV) analysis of the E magnitude at six different latitudes in Sweden and to express the maximum |E| that might be observed in 10, 50, and 100 years. We analyzed 10-s E data in Sweden, obtained from a 1-D model. This model incorporates 10-s geomagnetic measurements from the IMAGE network and the vertical Earth’s ground electrical conductivity in Sweden, extracted from a 3-D conductance map for the Fennoscandian region. Extreme E events tend to occur in clusters around geomagnetic disturbances (substorms and geomagnetic storms). Therefore, we applied two different methods to decluster the data. After declustering, Generalized Pareto (GP) distributions were fitted to the remaining extreme events that exceeded the 99.5th percentile. The EV analysis indicates that the shape parameter of the GP distribution depends on latitude. This implies that at higher geographic latitudes (64.52–68.02°N) the distribution decreases faster toward zero than at lower latitudes (58.26–62.25°N). As a result the expected maximum |E| in 100 years in central Sweden ranges between 4.0 and 8.5 V/km, while at higher latitudes, it ranges between 2.0 and 2.5 V/km, similar to the modeled geoelectric field values during the Halloween event in October 2003. In particular, around 60.50°N the distribution of extreme events exhibits the heaviest tail. When we additionally consider the effect of conductivity, the region of west Sweden around 60.50°N exhibits the largest expected maximum in 100 years with a value around 8.5 V/km. This is three times larger than the maximum modeled |E| at that latitude.

Han Zhang, Zhenyu Hong, Lai Wei et al.

To understand the sources and migration pattern of PM_2.5 in the Yangtze River Delta (YRD), China, the total carbon (TC) and total nitrogen (TN) concentrations and the corresponding stable isotope ratios (δ¹³C_TC and δ¹⁵N_TN) were determined in aerosol samples simultaneously collected from August 2014 to April 2015 at three different locations (Shanghai, Ningbo, Nanjing). Ningbo and Shanghai are geographically closer, the research results precisely divide Nanjing and the other two cities into two categories. Nanjing has a higher proportion of nitrogen in PM_2.5 (13.2–15.3%) than Shanghai and Ningbo (8.6–12.6%), and the correlation analysis shows that nitrogen components (mainly ammonium nitrogen) might be the main driving force for the formation of PM_2.5. The isotopes were proven to be sensitive sensors to reflect the impact of special events on PM_2.5. For example, compared to other seasons, δ¹³C_TC in autumn in the three cities are relatively depleted, indicating an input from biomass combustion to PM_2.5 at this time. On New Year’s Eve, three cities simultaneously observed enriched δ¹³C_TC due to the burning of fireworks. During the Qingming Festival, abnormally depleted nitrogen isotope ratios were observed, reflecting the vehicle exhaust pollution caused by people’s short travel. Isotopes are also used to trace the transport process of PM_2.5. Postponing the sampling date in Nanjing by one day increased the linear fit (r²) of δ¹³C_TC between Nanjing and Ningbo from 0.03 to 0.75, while that of δ¹⁵N_TN improved from 0.16 to 0.63, which means PM_2.5 might transport from Nanjing to Shanghai and Ningbo, and the transfer time takes one day.

Cecilia Fonseca Rivera, Dunia Hernández González, Milena Alpízar Tirzo et al.

En el presente informe se realiza una descripción del estado del clima en Cuba durante el 2020, a partir del análisis del comportamiento de determinados indicadores y variables climáticas, así como de algunos factores que regulan la variabilidad del clima en Cuba y la región. Estos indicadores proporcionan la información más relevante con relación a las variaciones que se produjeron en el clima en el pasado año. La temperatura media anual fue la más alta desde 1951, al alcanzar un valor de 1.17 °C por encima de la media histórica del período 1961-1990. La temperatura media de la década 2011-2020 es la más elevada de los registros, y el 2020 acentuó aún más la tendencia al incremento de la temperatura media anual en Cuba. En correspondencia, se rompieron 82 nuevos récords de temperatura máxima y se estableció el récord nacional de temperatura máxima absoluta de Cuba con un valor de 39.7°C en el mes de abril. Se reportaron además siete eventos extremos por calor, que ubican al 2020 como el segundo de mayor frecuencia en cuanto a la ocurrencia de estos eventos. La influencia del evento AENOS se reflejó en la activa temporada ciclónica, aunque solo afectaron a Cuba directamente dos tormentas tropicales: Laura y Eta. Las precipitaciones mostraron una variabilidad anual marcada, con bajos reportes en los primeros meses del año. Este comportamiento propició la ocurrencia de sequía meteorológica y agrícola en parte del territorio nacional, la que disminuyó con el comportamiento de las lluvias en los meses del período lluvioso.

Francesca Costabile, Maurizio Gualtieri, Carla Ancona et al.

Suspected detrimental health effects associated with ultrafine particles (UFPs) are impressive. However, epidemiological evidence is still limited. This is potentially due to challenges related to UFP exposure assessment and the lack of consensus on a standard methodology for UFPs. It is imperative to focus future health studies on those UFP metrics more likely to represent health effects. This is the purpose of this paper, where we extend the results obtained during the CARE (“Carbonaceous Aerosol in Rome and Environs”) experiment started in 2017 in Rome. The major purpose is to investigate features of airborne UFPs associated with pro-inflammatory and oxidative responses. Aerosol chemical, microphysical, and optical properties were measured, together with the oxidative potential, at temporal scales relevant for UFPs (minutes to hours). The biological responses were obtained using both in-vivo and in-vitro tests carried out directly under environmental conditions. Findings indicate that caution should be taken when assessing health-relevant exposure to UFPs through the conventional metrics like total particle number concentration and PM_2.5 and Black Carbon (BC) mass concentration. Conversely, we recommend adding to these, a UFP source apportionment analysis and indicators for both ultrafine black carbon and the size of particles providing most of the total surface area to available toxic molecules.

Nadya Moisseeva, Roland Stull

Current understanding of the buoyant rise and subsequent dispersion of smoke due to wildfires has been limited by the complexity of interactions between fire behavior and atmospheric conditions, as well as the uncertainty in model evaluation data. To assess the feasibility of using numerical models to address this knowledge gap, we designed a large-eddy simulation of a real-life prescribed burn using a coupled semi-emperical fire−atmosphere model. We used observational data to evaluate the simulated smoke plume, as well as to identify sources of model biases. The results suggest that the rise and dispersion of fire emissions are reasonably captured by the model, subject to accurate surface thermal forcing and relatively steady atmospheric conditions. Overall, encouraging model performance and the high level of detail offered by simulated data may help inform future smoke plume modeling work, plume-rise parameterizations and field experiment designs.

C. Kodama, Y. Yamada, A. Noda et al.

Chihiro KODAMA, Yohei YAMADA, Akira T. NODA Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan Kazuyoshi KIKUCHI International Pacific Research Center, University of Hawaii, Hawaii, USA Yoshiyuki KAJIKAWA RIKEN Advanced Institute for Computational Science, Kobe, Japan Tomoe NASUNO Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan Tomohiko TOMITA Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan Tsuyoshi YAMAURA RIKEN Advanced Institute for Computational Science, Kobe, Japan Hiroshi G. TAKAHASHI Tokyo Metropolitan University, Hachioji, Japan Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan Masayuki HARA Center for Environmental Science in Saitama, Kazo, Japan Yoshio KAWATANI Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan Masaki SATOH Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan and Masato SUGI Meteorological Research Institute, Tsukuba, Japan (Manuscript received 6 November 2014, in final form 17 March 2015)

M. Rezazadeh, P. Irannejad, Y. Shao

S. Boussetta, G. Balsamo, A. Beljaars et al.

Bo Hong, Hongqiao Qin, Borong Lin

Airflow behavior and indoor/outdoor PM2.5 dispersion in different building–tree grouping patterns depend significantly on the building–tree layouts and orientation towards the prevailing wind. By using a standard k-ε model and a revised generalized drift flux model, this study evaluated airflow fields and indoor/outdoor relationships for PM2.5 resulting from partly wind-induced natural ventilation in four hypothetical building–tree grouping patterns. Results showed that: (1) Patterns provide a variety of natural ventilation potential that relies on the wind influence, and buildings that deflect wind on the windward facade and separate airflow on the leeward facade have better ventilation potential; (2) Patterns where buildings and trees form a central space and a windward opening side towards the prevailing wind offer the best ventilation conditions; (3) Under the assumption that transported pollution sources are diluted through the inlet, the aerodynamics and deposition effects of trees cause the lower floors of a multi-storey building to be exposed to lower PM2.5 compared with upper floors, and lower indoor PM2.5 values were found close to the tree canopy; (4) Wind pressure differences across each flat showed a poor correlation (R2 = 0.059), with indoor PM2.5 concentrations; and (5) Patterns with the long facade of buildings and trees perpendicular to the prevailing wind have the lowest indoor PM2.5 concentrations.

P. Groenemeijer, T. Kühne

P. Murugavel, S. Pawar, V. Gopalakrishan

Nawhath Thanvisitthpon

This research investigates the impacts of the repetitive flooding on the inhabitants of the four flood-prone districts in Thailand’s central province of Ayutthaya: Pranakorn Si Ayutthaya, Sena, Bang Ban, and Pak Hai. In addition, the residents’ satisfaction levels with the flood relief efforts and operations of the local authorities were examined and analyzed. The research revealed that most local residents have adapted to co-exist with the repetitive floods, an example of which is the elevation of the houses a few meters above the ground where the living quarter is on the upper level. The findings also indicated that the repetitive flooding incurred substantial post-flood repair costs, in light of the low income-earning capabilities of the locals. However, the flood-recovery financial aids was incommensurate with the actual expenditures, contributing to the lowest average satisfaction score among the inhabitants with regard to the adequacy of the post-flood repair and restoration financial aid. Furthermore, the research identified the differences between districts on the satisfaction with the flood relief efforts. The disparity could be attributed to the extent of coordination and participation of the local residents and their local leaders in the flood-related measures.

Qinglong You, J. Min, Houbo Lin et al.

Monthly surface relative humidity (RH) data for 71 stations in the Tibetan Plateau (TP) provided by the National Meteorological Information Center/China Meteorological Administration are compared with corresponding grid points from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR hereafter) reanalysis. Mean climatologies, interannual variabilities, and trends calculated by the Mann‐Kendal method are analyzed during 1961–2013. The annual regional long‐term mean surface RH is 55.3%, with a clear maximum in summer (66.4%) and minimum in winter (44.9%). Compared with observations, NCEP/NCAR overestimates RH in all seasons, especially in spring (18.2%) and winter (17.8%). Mean annual regional surface RH has decreased by −0.23% decade−1 and even more rapidly in summer (−0.60% decade−1) and autumn (−0.39% decade−1). The reduction of surface RH is also captured by the NCEP/NCAR reanalysis at the surface, 400, 500, and 600 hPa. A particularly sharp reduction of RH since the mid‐1990s is evident in both data sets, in line with rapid warming over the plateau. This suggests that moisture supply to the plateau from the Arabian Sea and the Bay of Bengal is limited and that variability and trends of surface RH over the TP are not uniquely driven by the Clausius‐Clapeyron relationship.