scholarly journals Spatial and temporal variability of precipitation extreme indices in arid and semi-arid regions of Iran for the last half-century

Időjárás ◽  
2021 ◽  
Vol 125 (1) ◽  
pp. 83-104
Author(s):  
Sadegh Karimi ◽  
Hamid Nazaripour ◽  
Mohsen Hamidianpour
Keyword(s):  
Heavy Precipitation ◽  
Precipitation Variability ◽  
Precipitation Extreme ◽  
Statistical Testing ◽  
Systematic Change ◽  
Past Century ◽  
Wide Range ◽  
Value Range ◽  
Semi Arid ◽  
Extreme Indices

Precipitation variability analysis, on different spatial and temporal scales, has been of great concern during the past century because of the attention given to global climate change by the scientific community. According to some recent studies, the Iranian territory has been experienced a precipitation variability, especially in the last 50 years, and the arid and semi-arid areas seem to be more affected. The present study aims to analyze precipitation extreme indices over a wide time interval and a wide area, detecting potential trends and assessing their significance. The investigation is based on a wide range of daily and multi-day precipitation statistics encompassing basic characteristics and heavy precipitation. Two different methods of trend analysis and statistical testing are applied, depending on the nature of the statistics. Linear regression is used for statistics with a continuous value range, and logistic regression is used for statistics with a discrete value range. The trends are calculated on annual and seasonal bases for the years 1951–2007. Statistical analysis of the database highlight that a clear trend signal is found with a high number of sites with a statistically significant trend. In winter, significant increases are found for all statistics related to precipitation strength and occurrence. In spring, statistically, significant increases are found only for the statistics related to heavy precipitation, whereas precipitation frequency and occurrence statistics show little systematic change. The trend signal is strongest in highlands and mountainous terrains. In autumn and summer, the heavy and basic precipitation statistics did not show statistically significant trends.

scholarly journals Trends of precipitation extreme indices over a subtropical semi-arid area using PERSIANN-CDR

2016 ◽  
Vol 130 (1-2) ◽  
pp. 249-260 ◽  
Author(s):  
Pari-Sima Katiraie-Boroujerdy ◽  
Hamed Ashouri ◽  
Kuo-lin Hsu ◽  
Soroosh Sorooshian
Keyword(s):  
Arid Area ◽  
Precipitation Extreme ◽  
Semi Arid ◽  
Extreme Indices

scholarly journals Observed Trends and Changes in Temperature and Precipitation Extreme Indices over Myanmar

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 477 ◽  
Author(s):  
Kyu Kyu Sein ◽  
Amnat Chidthaisong ◽  
and Kyaw Lwin Oo
Keyword(s):  
Minimum Temperature ◽  
Southern Oscillation ◽  
Heavy Precipitation ◽  
Precipitation Anomaly ◽  
Precipitation Extreme ◽  
Maximum Temperature ◽  
Climate Extreme ◽  
Temperature And Precipitation ◽  
Increasing Trends ◽  
Extreme Indices

Projected increase in frequency and severity of extreme events are important threat brought by climate change. Thus, there is a need to understand the dynamics and magnitude of climate extreme at local and regional level. This study examines the patterns of annual trends and changes of extreme daily temperature and precipitation in Myanmar for the period of 1981 to 2015 using the RClimDex 1.1 software. The trends of maximum and minimum temperature show significant warming trends (p < 0.001) across Myanmar. From 2009 to 2015, the maximum temperature anomaly has continuously increased by 0.5 °C for all years except 2011. The larger rise in both maximum and minimum temperature observed after 2000 suggests that, overall, days and nights are becoming hotter for the entirety of Myanmar over this recent period. Furthermore, our works also show that the temperature extreme indices of warm days and warm nights have increased, whereas the frequency of cool days and cool nights have decreased. Our analysis also reveals that increasing trends in precipitation anomaly were not significant during 1981–2015. On the contrary, slight increasing trends towards wetter conditions were observed with a rate of 76.52 mm/decade during the study period. The other precipitation extreme indicators—namely, annual total precipitation (PRCPTOT), heavy precipitation days (R20mm), extreme wet days precipitation (R99p), and consecutive wet days (CWD)—are consistent with warming trends. Additionally, the relationship between inter-annual variability in the climate extremes indices and Oceanic Niño Index (ONI) patterns was also examined with a focus on the influence of the El Niño-Southern Oscillation (ENSO) phenomenon.

scholarly journals Recent Advances in Enzymatic and Non-Enzymatic Electrochemical Glucose Sensing

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4672
Author(s):  
Mohamed H. Hassan ◽  
Cian Vyas ◽  
Bruce Grieve ◽  
Paulo Bartolo
Keyword(s):  
Noble Metals ◽  
Direct Electrochemistry ◽  
Glucose Sensing ◽  
Glucose Sensors ◽  
Diabetic Patients ◽  
Past Century ◽  
Industrial Sectors ◽  
Recent Advances ◽  
Wide Range ◽  
Sensitivity And Selectivity

The detection of glucose is crucial in the management of diabetes and other medical conditions but also crucial in a wide range of industries such as food and beverages. The development of glucose sensors in the past century has allowed diabetic patients to effectively manage their disease and has saved lives. First-generation glucose sensors have considerable limitations in sensitivity and selectivity which has spurred the development of more advanced approaches for both the medical and industrial sectors. The wide range of application areas has resulted in a range of materials and fabrication techniques to produce novel glucose sensors that have higher sensitivity and selectivity, lower cost, and are simpler to use. A major focus has been on the development of enzymatic electrochemical sensors, typically using glucose oxidase. However, non-enzymatic approaches using direct electrochemistry of glucose on noble metals are now a viable approach in glucose biosensor design. This review discusses the mechanisms of electrochemical glucose sensing with a focus on the different generations of enzymatic-based sensors, their recent advances, and provides an overview of the next generation of non-enzymatic sensors. Advancements in manufacturing techniques and materials are key in propelling the field of glucose sensing, however, significant limitations remain which are highlighted in this review and requires addressing to obtain a more stable, sensitive, selective, cost efficient, and real-time glucose sensor.

Changes in temperature and precipitation extreme indices over China: analysis of a high-resolution grid dataset

2015 ◽  
Vol 36 (3) ◽  
pp. 1051-1066 ◽  
Author(s):  
Botao Zhou ◽  
Ying Xu ◽  
Jia Wu ◽  
Siyan Dong ◽  
Ying Shi
Keyword(s):  
High Resolution ◽  
Precipitation Extreme ◽  
Temperature And Precipitation ◽  
Extreme Indices

scholarly journals Is Annual Recharge Coefficient a Valid Concept in Arid and Semi-Arid Region?

2017 ◽  
Author(s):  
Yiben Cheng ◽  
Hongbin Zhan ◽  
Wenbin Yang ◽  
Hongzhong Dang ◽  
Wei Li
Keyword(s):  
Arid Regions ◽  
Groundwater Resources ◽  
Heavy Precipitation ◽  
Annual Precipitation ◽  
Precipitation Event ◽  
Precipitation Pattern ◽  
Deep Soil ◽  
Bare Sand ◽  
Sand Land ◽  
Semi Arid

Abstract. Deep soil recharge (DSR) (at depth more than 200 cm) is an important part of water circulation in arid and semi-arid regions. Quantitative monitoring of DSR is of great importance to assess water resources and study water balance in arid and semi-arid regions. Simple estimates of recharge based on fixed fractions of annual precipitation are misleading because they do not reflect the plant and soil factors controlling recharge. This study used a typical bare land on the Eastern margin of Mu Us Sandy Land of China an example to illustrate a new lysimeter method of measuring DSR underneath bare sand land in arid and semi-arid regions. Positioning monitoring was done on precipitation and DSR measurement underneath mobile sand dunes from 2013 to 2015 in the study area. Results showed that use of a constant recharge coefficient for estimating DSR in bare sand land in arid and semi-arid regions is questionable and could lead to considerable errors. It appeared that DSR in those regions was influenced by precipitation pattern, and was closely correlated with spontaneous heavy precipitation (defined for an event with more than 10 mm precipitation) other than the average precipitation strength. This study showed that as much as 42 % of precipitation in a single heavy precipitation event can be transformed into DSR. During the observation period, the maximum annual DSR could make up to 24.33 % of the annual precipitation. This study provided a reliable method of estimating DSR in sandy area of arid and semi-arid regions, which is valuable for managing groundwater resources and ecological restoration in those regions.

Factors contributory to fire occurrences in two populated areas in the American southwest

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Susanna T.Y. Tong ◽  
Shitian Wan ◽  
Yuhe Gao
Keyword(s):  
Population Growth ◽  
Fire Regimes ◽  
American Southwest ◽  
Arid Areas ◽  
Vegetative Cover ◽  
Content Type ◽  
Clark County ◽  
Temporal Relationships ◽  
Wide Range ◽  
Semi Arid

PurposeThis study aims to further understand the factors contributory to fire occurrences in two semi-arid regions in the American Southwest, Clark County in Nevada and Maricopa and Pinal Counties in Arizona.Design/methodology/approachStatistical and geographic information system analyses were employed to examine the spatial and temporal relationships of various natural and human-caused factors with fire incidences.FindingsAngström fire danger index, average amount of rainfall one month prior, extent of forests and grasslands, and proximities to secondary roads and population centers have significant relationships with fire events.Research limitations/implicationsThe importance of the factors contributory to fire occurrence is site-specific even in areas with similar climatic regimes and varies among different geographic regions; as such, researchers will need to conduct specific investigation of each study area.Practical implicationsThe findings of this study can be instrumental in facilitating fire managers to derive more informed strategies in fire prevention and management.Originality/valueWhile there are many studies on fire, most of them are conducted in wet regions with a lot of vegetative cover; not much work is done on arid areas. This paper considered and compared the spatial and temporal relationships of a wide range of natural and human-caused factors with fire events in two semi-arid areas. The intent was to assess the relative importance of these factors in areas even with similar climatic regimes. As our world is facing unprecedented changes in terms of climate and population growth, it is paramount to have an enhanced understanding of the impacts of these changes on fire regimes. The study areas are hot and dry, and they are located in the wildland–urban interfaces with rapid population growth and urbanization; as such, the research findings may contribute to existing literature.

scholarly journals The effect of atmospheric rivers on cold-season heavy precipitation events in Iran

2020 ◽  
Author(s):  
Neda Esfandiari ◽  
Hassan Lashkari
Keyword(s):  
Extreme Events ◽  
Heavy Precipitation ◽  
Cold Season ◽  
Western Slope ◽  
Arid Areas ◽  
Gulf Of Aden ◽  
Zagros Mountains ◽  
Atmospheric Rivers ◽  
Semi Arid ◽  
Precipitation Events

Abstract Atmospheric rivers (ARs) as massive and concentrated water vapour paths can have a critical impact on extreme events in arid and semi-arid areas. This study investigated the effect of ARs on heavy precipitation events during the cold, rainy months (November–April) in Iran for 11 years. The results showed that 107 ARs had an influence on heavy precipitation, which providing partial moisture for Iran's precipitation. On average, 11 heavy precipitation days were linked to the presence of ARs in the six cold months of each year. During the study period, ARs accounted for almost 20–50% of the country's total heavy precipitation monthly. Although most ARs entered the country from the south through coastal areas, the western part of Iran, especially elevated stations along the western slope of the Zagros Mountains, received the highest heavy precipitation. Accordingly, about 66% of ARs directly originated from the Red Sea and the Gulf of Aden. Moreover, December experienced the highest frequency of ARs linked to heavy precipitation during the statistical period.

scholarly journals Rapid climate-driven evolution of the invasive species Mytilus galloprovincialis over the past century

2020 ◽  
Vol 3 (1) ◽  
pp. 14-29
Author(s):  
Guo-Dong Han ◽  
Yun-Wei Dong
Keyword(s):  
Invasive Species ◽  
Genetic Variation ◽  
Mytilus Galloprovincialis ◽  
Climatic Factors ◽  
Northwestern Pacific ◽  
Past Century ◽  
Nucleotide Polymorphisms ◽  
Adaptive Genetic Variation ◽  
The Past ◽  
Wide Range

Climate-driven adaptive genetic variation is one of the most important ways for organisms to tolerate environmental change and succeed in altered environments. To understand rapid climate-driven evolution, and how this evolution might shift biogeographic distributions in response to global change, we measured the adaptive genetic variation to the local environment of a marine invasive species Mytilus galloprovincialis. The genetic structure of eight populations from the Mediterranean Sea, northeastern Atlantic, northeastern Pacific, and northwestern Pacific were determined using genome-wide screens for single nucleotide polymorphisms. The relationships of genetic variation to environmental (seawater and air) temperature were analyzed using redundancy analysis and BayeScEnv analysis to evaluate the impacts of temperature on the genetic divergences among these eight populations. We found that the genetic compositions were significantly different among populations and the adaptive genetic variation was associated with temperature variables. Further, we identified some genetic markers exhibiting signatures of divergent selection in association with environmental features that can be used in the future to closely monitor adaptive variation in this species. Our results suggest that divergent climatic factors have driven adaptive genetic variation in M. galloprovincialis over the past century. The rapid evolutionary adaptation has played a pivotal role in enabling this species to invade a wide range of thermal habitats successfully. Species like M. galloprovincialis that possess high levels of genetic variation may not only be especially capable of invading new habitats with different environmental conditions, but also poised to cope rapidly and successfully with rising global temperatures.

Intrinsic Frequency Tuning in ELL Pyramidal Cells Varies Across Electrosensory Maps

2008 ◽  
Vol 99 (5) ◽  
pp. 2641-2655 ◽  
Author(s):  
W. Hamish Mehaffey ◽  
Leonard Maler ◽  
Ray W. Turner
Keyword(s):  
Sensory Input ◽  
Frequency Tuning ◽  
Electric Organ Discharge ◽  
Electric Organ ◽  
Pyramidal Cells ◽  
Weakly Electric Fish ◽  
Systematic Change ◽  
Specific Stimulus ◽  
Wide Range ◽  
Sensory Maps

The tuning of neuronal responsiveness to specific stimulus frequencies is an important computation across many sensory modalities. The weakly electric fish Apteronotus leptorhynchus detects amplitude modulations of a self-generated quasi-sinusoidal electric organ discharge to sense its environment. These fish have to parse a complicated electrosensory environment with a wide range of possible frequency content. One solution has been to create multiple representations of the sensory input across distinct maps in the electrosensory lateral line lobe (ELL) that participate in distinct behavioral functions. E- and I-type pyramidal cells in the ELL that process sensory input further exhibit a preferred range of stimulus frequencies in relation to the different behaviors and sensory maps. We tested the hypothesis that variations in the intrinsic spiking mechanism of E- and I-type pyramidal cells contribute to map-specific frequency tuning. We find that E-cells exhibit a systematic change in their intrinsic spike characteristics and frequency tuning across sensory maps, whereas I-cells are constant in both spike characteristics and frequency tuning. As frequency tuning becomes more high-pass in E-cells, the refractory variables of spike half-width and afterhyperpolarization magnitude increase, spike threshold increases, adaptation becomes faster, and the gain of the spiking response decreases. These findings indicate that frequency tuning across sensory maps in the ELL is supported by differences in the intrinsic spike characteristics of pyramidal cells, revealing a link between cellular biophysical properties and signal processing in sensory maps with defined behavioral roles.

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