scholarly journals An Object-based Climatology of Precipitation Systems in Sydney, Australia

2021 ◽  
Author(s):  
Hooman Ayat ◽  
Jason P. Evans ◽  
Steven C. Sherwood ◽  
Joshua Soderholm
Keyword(s):  
Cell Tracking ◽  
Clustering Algorithms ◽  
Warm Season ◽  
Radar Data ◽  
Cold Season ◽  
Translation Speed ◽  
Precipitation System ◽  
Different Seasons ◽  
Storm Characteristics ◽  
Sydney Australia

Abstract The climate is warming and this is changing some aspects of storms, but we have relatively little knowledge of storm characteristics beyond intensity, which limits our understanding of storms overall. In this study, we apply a cell-tracking algorithm to 20 years of radar data at a mid-latitude coastal-site (Sydney, Australia), to establish a regional precipitation system climatology. The results show that extreme storms in terms of translation-speed, size and rainfall intensity usually occur in the warm season, and are slower and more intense over land between ~10am and ~8pm (AEST), peaking in the afternoon. Precipitation systems are more frequent in the cold season and often initiate over the ocean and move northward, leading to precipitation mostly over the ocean. Using clustering algorithms, we have found five precipitation system types with distinct properties, occurring throughout the year but peaking in different seasons. While overall rainfall statistics don't show any link to climate modes, links do appear for some system types using a multivariate approach. This climatology for a variety of precipitation system characteristics will allow future study of any changes in these characteristics due to climate change.

scholarly journals A Radar Object-Based Examination of Rain System Climatology and Including Climate Variability

2021 ◽  
Author(s):  
Hooman Ayat ◽  
Jason P. Evans ◽  
Steven C. Sherwood ◽  
Joshua Soderholm
Keyword(s):  
Cell Tracking ◽  
Clustering Algorithms ◽  
Warm Season ◽  
Radar Data ◽  
Cold Season ◽  
Translation Speed ◽  
Different Seasons ◽  
A Cell ◽  
Storm Characteristics ◽  
Rainfall Statistics

Abstract We know the climate is warming and this is changing some aspects of storms, but we have little knowledge of storm characteristics beyond intensity, which limits our understanding of storms overall. In this study, we apply a cell-tracking algorithm to 20 years of radar data at a mid-latitude coastal-site (Sydney, Australia), to establish a regional storm climatology. The results show that extreme storms in terms of translation-speed, size and rainfall intensity usually occur in the warm season, and are slower and more intense over land between ~10am and ~8pm (AEST), peaking in the afternoon. Storms are more frequent in the cold season and often initiate over the ocean and move northward, leading to precipitation mostly over the ocean. Using clustering algorithms, we have found five storm types with distinct properties, occurring throughout the year but peaking in different seasons. While overall rainfall statistics don't show any link to climate modes, links do appear for some storm types using a multivariate approach. This climatology for a variety of storm characteristics will allow future study of any changes in these characteristics due to climate change.

scholarly journals The role of phytophysiognomies and seasonality on the structure of ground-dwelling anuran (Amphibia) in the Pampa biome, southern Brazil

2013 ◽  
Vol 85 (3) ◽  
pp. 1105-1116 ◽  
Author(s):  
FRANCIELE P. MARAGNO ◽  
TIAGO G. SANTOS ◽  
SONIA Z. CECHIN
Keyword(s):  
Paired Comparison ◽  
Warm Season ◽  
Cold Season ◽  
Pitfall Traps ◽  
Southern Brazil ◽  
Environmental Features ◽  
Pampa Biome ◽  
Different Seasons ◽  
Pseudis Minuta

ABSTRACT Considering that habitat use by amphibians is related both with climate and environmental features, we tested the hypothesis that anuran assemblages found in different phytophysiognomies and in different seasons vary in structure. Additionally, we searched for species which can be indicators of habitat and seasons. The study was conducted in the Pampa biome, southern Brazil. Sampling was done through pitfall traps placed in three phytophysiognomies: grassland, ecotone grassland/forest; and forest. The seasonality factor was created by grouping months in warn and cold seasons. Sixteen species were found and the assemblages were influenced both by phytophysiognomies and climatic seasonality. In a paired comparison, the three phytophysiognomies differed in structure of assemblage from each other. Physalaemus henselii, P. riograndensis, Pseudopaludicola falcipes and Pseudis minuta were indicators of ecotone. Leptodactylus gracilis and Physalaemus biligonigerus were indicators of grassland. None species was indicator of forest. Most of the species were indicators of warm season: Elachistocleis bicolor, Leptodactylus fuscus, L. gracilis, L. latinasus, L. latrans, L. mystacinus, Physalaemus biligonigerus, P. cuvieri and Pseudis minuta. None species was indicator of cold season. We found that even for species of open areas, as Pampa, heterogeneous phytophysiognomies are important for maintaining abundance and constancy of populations of anuran.

scholarly journals An Objectively Determined Blocking Index and its Northern Hemisphere Climatology

2013 ◽  
Vol 27 (8) ◽  
pp. 2948-2970 ◽  
Author(s):  
David Small ◽  
Eyad Atallah ◽  
John R. Gyakum
Keyword(s):  
Northern Hemisphere ◽  
Systematic Approach ◽  
Intraseasonal Variability ◽  
Warm Season ◽  
Cold Season ◽  
Central Pacific ◽  
Anticyclonic Circulation ◽  
Blocking Activity ◽  
Different Seasons ◽  
Blocking Index

Abstract A modified blocking index is defined based on vertically integrated potential vorticity. The application of this index identifies blocking activity over the Northern Hemisphere during all seasons. The index is developed by systematically identifying the magnitude and spatial scale that best characterizes persistent anticyclonic circulation anomalies in different seasons. By applying a systematic approach to the detection of blocking, the interannual, seasonal, and intraseasonal patterns of blocking frequency across the Northern Hemisphere are able to be characterized. The results are consistent with previous studies in finding that blocking is more frequent in the cold season months than in the warm season, although the results suggest that blocking occurs much more frequently in the summer and fall than many studies have previously reported. By examining blocking frequency monthly, interesting patterns of intraseasonal variability are found, especially over the central Pacific in August and the eastern Pacific in September and October, where blocking is nearly as frequent as in the winter. Possible explanations for this intraseasonal variability are discussed.

scholarly journals Assessment of the Spatial and Seasonal Variation of the Error–Intensity Relationship in Satellite-Based Precipitation Measurements Using an Adaptive Parametric Model

2015 ◽  
Vol 16 (4) ◽  
pp. 1700-1716 ◽  
Author(s):  
Hao Liu ◽  
Soroosh Sorooshian ◽  
Xiaogang Gao
Keyword(s):  
Warm Season ◽  
Stage Iv ◽  
Cold Season ◽  
Parametric Model ◽  
Spatial And Seasonal Variation ◽  
Number Of Factors ◽  
Proposed Model ◽  
Different Seasons ◽  
Pdf Model ◽  
The Relationship

Abstract Studies have been reported about the efficacy of satellites for measuring precipitation and about quantifying their errors. Based on these studies, the errors are associated with a number of factors, among them, intensity, location, climate, and season of the year. Several error models have been proposed to assess the relationship between the error and the rainfall intensity. However, it is unknown whether these models are adaptive to different seasons, different regions, or different types of satellite-based estimates. Therefore, how the error–intensity relationship varies with the season or region is unclear. To investigate these issues, a parametric joint pdf model is proposed to analyze and study the 9-yr satellite-derived precipitation datasets of Climate Prediction Center (CPC) morphing technique (CMORPH); PERSIANN; and the real-time TRMM product 3B42, version 7 (TRMM-3B42-RTV7). The NEXRAD Stage IV product is the ground reference. The adaptability of the proposed model is verified by applying it to three locations (Oklahoma, Montana, and Florida) and by applying it to cold season, warm season, and the entire year. Then, the heteroscedasticities in the errors of satellite-based precipitation measurements are investigated using the proposed model under those scenarios. The results show that the joint pdfs have the same formulation under these scenarios, whereas their parameter sets were adaptively adjusted. This parametric model reveals detailed information about the spatial and seasonal variations of the satellite-based precipitation measurements. It is found that the shape of the conditional pdf shifts across the intensity ranges. At the ~10–20 mm day−1 range, the conditional pdf is L shaped, while at the ~40–60 mm day−1 range, it becomes more bell shaped. It is also concluded that no single satellite-based precipitation product outperforms others with respect to the different scenarios (i.e., seasons, regions, and climates).

scholarly journals Significant seasonal changes in optical properties of brown carbon in the mid-latitude atmosphere

2019 ◽  
Author(s):  
Heejun Han ◽  
Guebuem Kim ◽  
Kyung-Hoon Shin ◽  
Dong-Hun Lee
Keyword(s):  
Seasonal Changes ◽  
Organic Aerosols ◽  
Warm Season ◽  
Cold Season ◽  
Water Soluble ◽  
Significant Shift ◽  
Brown Carbon ◽  
Back Trajectories ◽  
Different Seasons ◽  
Property Changes

Abstract. Atmospheric brown carbon (BrC) plays significant roles in the light absorption and photochemistry of the atmosphere. Although the occurrence and sources of BrC have been studied extensively, its removal processes and optical characteristics in the atmosphere have been poorly understood. In this study, we examined the seasonal changes in sources and sinks of BrC and water-soluble organic carbon (WSOC) in the atmosphere of Seoul, Korea. Our results showed that the concentrations of BrC and WSOC decreased by approximately 80 % and 30 %, respectively, from the cold season (Oct–Jan) to the warm season (Jun–Sep). Excitation–emission matrix (EEM) spectra showed that the humic-like substance (HULIS) was the dominant fraction of BrC as the other components were not measurable. The air mass back trajectories of fire burning practices and the variations in K and V contents in the water-soluble aerosols during all seasons showed no measureable decrease in input of biomass-burning sources in summer. However, there was a significant shift in photo-resistivity of light-absorbing organic aerosols in the summer, indicating significantly larger removals of ultraviolet (UV) degradable BrC. This was confirmed by laboratory UV radiation experiments on the optical property changes of BrC and WSOC in aerosol samples. Thus, our results suggest that the photo-degradation has dominant roles in controlling the quantity and quality of light-absorbing organic aerosols in the different seasons in the mid-latitude atmosphere.

scholarly journals Significant seasonal changes in optical properties of brown carbon in the midlatitude atmosphere

2020 ◽  
Vol 20 (5) ◽  
pp. 2709-2718 ◽  
Author(s):  
Heejun Han ◽  
Guebuem Kim ◽  
Hojong Seo ◽  
Kyung-Hoon Shin ◽  
Dong-Hun Lee
Keyword(s):  
Seasonal Changes ◽  
Organic Aerosols ◽  
Warm Season ◽  
Cold Season ◽  
Water Soluble ◽  
Significant Shift ◽  
Brown Carbon ◽  
Back Trajectories ◽  
Different Seasons ◽  
Property Changes

Abstract. Atmospheric brown carbon (BrC) plays significant roles in the light absorption and photochemistry of the atmosphere. Although the sources and occurrences of BrC have been studied extensively, its removal processes and optical characteristics in the atmosphere have been poorly understood. In this study, we examined the seasonal changes in sources and sinks of BrC and water-soluble organic carbon (WSOC) in the atmosphere of Seoul, South Korea. Our results showed that the concentrations of BrC and WSOC decreased by approximately 80 % and 30 %, respectively, from the cold season (October–January) to the warm season (June–September). Excitation–emission matrix (EEM) spectra showed that the humic-like substance (HULIS) was the dominant fraction of BrC as the other components were not measurable. The air mass back trajectories of fire burning practices and the variations in non-crustal potassium (K) and vanadium (V) contents in the water-soluble aerosols during all seasons showed no measurable decrease in input of biomass-burning sources in summer. However, there was a significant shift in photo-resistivity of light-absorbing organic aerosols in the summer, indicating larger removals of ultraviolet (UV) degradable BrC. This trend is supported by laboratory UV radiation experiments on the optical property changes of BrC and WSOC in aerosol samples. Thus, our results suggest that the photodegradation has dominant roles in controlling the quantity and quality of light-absorbing organic aerosols in the different seasons in the midlatitude atmosphere.

scholarly journals SEASON DYNAMICS OF THE TEMPERATURE MODE OF BILOOZERSKYI MASSIVE OF RIVNE NATURAL RESERVE

2019 ◽  
pp. 83-92
Author(s):  
Oleksandr Koval
Keyword(s):  
Air Temperature ◽  
Graphical Models ◽  
Temperature Regime ◽  
Warm Season ◽  
Cold Season ◽  
Educational Process ◽  
Rate Of Change ◽  
Practical Significance ◽  
Air Masses ◽  
Different Seasons

Purpose. The purpose of the research is to analyze the temperature regime of the Biloozerskyi massive of Rivne Nature Reserve according to the data of the three nearest meteorological stations and to identify its dynamics and patterns. Methods. In the work are used the results of observations of the air temperature of the meteorological stations in Sarny, Lyubeshiv and Manevychi for the period of 2006-2018, which are freely available on the Internet: http://www.pogodaiklimat.ru. Climatological information was analyzed during the research. Mathematical statistics calculations have been applied to determine the decade air temperatures. Techniques for building graphical models (Excel software) for the annual course of air temperature were used. Graphic models set the date of transition of air temperature across thresholds, the length of periods with different temperatures and the length of periods with winter thaw and high summer temperatures. The work is based on statistical, analytical, comparative, graphic and descriptive research methods. Results. The daily, ten-day, monthly, annual, and long-term values of air temperature were analyzed and the date of steady transition of average daily air temperature across thresholds was established. The dynamics of starting and ending dates of different seasons and their duration are investigated. It is established that the duration of different seasons varies and varies significantly over the years. The cold season covers the winter and is characterized by alternation of cold and warm periods: the flow of cold air masses is accompanied by a decrease in air temperature, and the flow of warm air masses is accompanied by short or long thaws. In general, most of the winter is thawed days. The warm season covers spring, summer and autumn. Spring is the least longest and most dynamic period of the year. According to the peculiarities of the development of circulation processes and the rate of change of air temperature, spring and autumn are divided into several periods. The division of the transitional seasons into periods is conditioned by the beginning and the end of the warm period and the periods of vegetation and active vegetation. Summer is the longest period of the year. The summer is characterized by periods with high temperatures, when maximum temperatures are recorded in different grades. Scientific novelty. The research of the temperature regime of the protected area under the conditions of modern climate change is carried out. The dates of beginning and ending of different seasons, their duration and dynamics are established and regularities are formed. The practical significance. The materials of the research can be used for further meteorological research of nature reserves, for the needs of recreation, agrometeorology and in the educational process in the study of regional disciplines.

scholarly journals Temperature and Relative Humidity Profile Retrieval from Fengyun-3D/HIRAS in the Arctic Region

2021 ◽  
Vol 13 (10) ◽  
pp. 1884
Author(s):  
Jingjing Hu ◽  
Yansong Bao ◽  
Jian Liu ◽  
Hui Liu ◽  
George P. Petropoulos ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Real Time ◽  
Wide Spectrum ◽  
Warm Season ◽  
Arctic Region ◽  
Cold Season ◽  
The Arctic ◽  
Practical Applications ◽  
A New Technique ◽  
The Arctic Region

The acquisition of real-time temperature and relative humidity (RH) profiles in the Arctic is of great significance for the study of the Arctic’s climate and Arctic scientific research. However, the operational algorithm of Fengyun-3D only takes into account areas within 60°N, the innovation of this work is that a new technique based on Neural Network (NN) algorithm was proposed, which can retrieve these parameters in real time from the Fengyun-3D Hyperspectral Infrared Radiation Atmospheric Sounding (HIRAS) observations in the Arctic region. Considering the difficulty of obtaining a large amount of actual observation (such as radiosonde) in the Arctic region, collocated ERA5 data from European Centre for Medium-Range Weather Forecasts (ECMWF) and HIRAS observations were used to train the neural networks (NNs). Brightness temperature and training targets were classified using two variables: season (warm season and cold season) and surface type (ocean and land). NNs-based retrievals were compared with ERA5 data and radiosonde observations (RAOBs) independent of the NN training sets. Results showed that (1) the NNs retrievals accuracy is generally higher on warm season and ocean; (2) the root-mean-square error (RMSE) of retrieved profiles is generally slightly higher in the RAOB comparisons than in the ERA5 comparisons, but the variation trend of errors with height is consistent; (3) the retrieved profiles by the NN method are closer to ERA5, comparing with the AIRS products. All the results demonstrated the potential value in time and space of NN algorithm in retrieving temperature and relative humidity profiles of the Arctic region from HIRAS observations under clear-sky conditions. As such, the proposed NN algorithm provides a valuable pathway for retrieving reliably temperature and RH profiles from HIRAS observations in the Arctic region, providing information of practical value in a wide spectrum of practical applications and research investigations alike.All in all, our work has important implications in broadening Fengyun-3D’s operational implementation range from within 60°N to the Arctic region.

scholarly journals Late Dorset architecture on Little Cornwallis Island, Nunavut

2005 ◽  
Vol 27 (1-2) ◽  
pp. 255-280 ◽  
Author(s):  
Genevieve LeMoine ◽  
James Helmer ◽  
Bjarne Grønnow
Keyword(s):  
Warm Season ◽  
Cold Season ◽  
Nuclear Families ◽  
Construction Techniques ◽  
Architectural Features ◽  
Size Number ◽  
Cornwallis Island

Abstract Late Dorset dwellings from two sites on Little Cornwallis Island (Nunavut) illustrate the diversity of architectural forms from this period. Ten architectural features are described. They include five tent rings, ascribed to warm season occupations, and five rectangular semi-subterranean houses with axial features, including one exceptionally well-preserved example, ascribed to cold season occupations. Variations in size, number of hearths, and construction techniques are examined and the use of both types of structures to house multiple nuclear families is suggested.

scholarly journals Protozooplankton characterization of two contrasting sites in a tropical coastal ecosystem (Guanabara Bay, RJ)

2007 ◽  
Vol 55 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Eli Ana Traversim Gomes ◽  
Viviane Severiano dos Santos ◽  
Denise Rivera Tenenbaum ◽  
Maria Célia Villac
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Food Web ◽  
Warm Season ◽  
Descriptive Study ◽  
Cold Season ◽  
Guanabara Bay ◽  
Trophic Conditions ◽  
Plankton Dynamics

Much time and resources have been invested in understanding plankton dynamics in Guanabara Bay (Brazil), but no attention has been devoted to the protozooplankton. To fulfill this lacuna, abundance and composition of protozooplankton were investigated from January to December - 2000 in fortnightly surface water samplings at two distinct water quality sites (Urca - closer to the bay entrance, more saline and cleaner waters; Ramos - inner reaches, hypereutrophic waters). The density at Urca (10³ - 10(5) cell.l-1) was one to three orders of magnitude lower than at Ramos (10(4) - 10(5) cell.l-1). A seasonal trend for nanoplankton and protozooplankton was more evident at Urca, but both sites had lower densities during the colder period. Small heterotrophic dinoflagellates (20-30 mm) were dominant in over 50% of the samples. The protozooplankton abundance and composition reflected the distinct trophic conditions states found at the bay. During the wet-warm season, non-oligotrich ciliates were representative of Ramos site with Gymnodiniaceae dinoflagellates, while tintinnids and heterotrophic dinoflagellates were predominantly found at Urca mainly during the dry-cold season. This first descriptive study towards the understanding of the intricate relationships among the microbial food web components reveals that protozooplankton can be a good indicator of water quality conditions at the bay.

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