scholarly journals Spatial and temporal variability of Standardized Precipitation Index over Indochina Peninsula

2016 ◽  
Vol 42 (1) ◽  
pp. 221 ◽  
Author(s):  
T. M. Vu ◽  
A. Mishra
Keyword(s):  
Temporal Variability ◽  
Standardized Precipitation Index ◽  
Climatic Conditions ◽  
Dry Season ◽  
Precipitation Index ◽  
Trend Test ◽  
Spatial And Temporal Variability ◽  
Wet Season ◽  
Indochina Peninsula ◽  
Red River Delta

Indochina Peninsula has abundant water resources; however, most of the rain falls during the wet season. An arid condition is quite pronounced throughout the dry season. The majority of population depends on the agriculture as the main source of livelihood income. It is, therefore, important to study the drought and wetness over the region because crops are vulnerable to extreme climatic conditions. We used gridded precipitation APHRODITE and Standardized Precipitation Index (SPI) to evaluate the spatial and temporal variability of drought and wetness over Indochina peninsula. Nonparametric Modified Mann-Kendall (MMK) trend test was applied to determine the SPI trends over this region. There is a decrease in precipitation over a large part of Indochina during winter (dry season) and an increasing pattern during summer (rainy season). The increasing trend of SPI indicates an increase in wet condition over most parts of Indochina peninsula except for Red River Delta in Vietnam, central parts of Vietnam/Laos and western parts of Cambodia.

scholarly journals Negative regional Standardized Precipitation Index trends prevail in the Mexico’s state of Zacatecas.

2019 ◽  
Vol 37 (4) ◽  
pp. 487
Author(s):  
Rafael Magallanes-Quintanar ◽  
Fidel Blanco-Macías ◽  
Erick Carlos Galván-Tejada ◽  
Jorge Isaac Galván-Tejada ◽  
Miguel Márquez-Madrid ◽  
...  
Keyword(s):  
Time Series ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Trend Test ◽  
Spatial And Temporal Variability ◽  
Monthly Precipitation ◽  
Precipitation Time Series ◽  
Groundwater Levels ◽  
Sen’S Slope ◽  
Precipitation Regimes

As the earth atmosphere warms, it is unclear how the precipitation will change or how these changes will impact regional rainfall. For the study of spatial and temporal variability of rainfall, several indexes have been developed. The Standardized Precipitation Index (SPI) that only involves recorded rainfall data has been used as a tool for climatic zone classif ication and a drought indicator. Then, the aims of the present study were: 1) to cluster monthly precipitation time series into groups that represent regions under the basis of similar precipitation regimes, 2) to compute regional SPI’s using all the members (time series) of each cluster, and 3) to estimate trends of the regional SPI’s. The cluster analysis approach was used to identify four groups of monthly precipitation time series that represent regions of similar precipitation regimes. Afterwards, regional SPI’s were estimated using all the members of each cluster. Finally, four regional SPI trends were estimated by means of the Mann-Kendall trend test and Sen’s slope estimator. Estimated decreasing SPI trends imply prevail of negative values at the end of the study period (1964-2014), which indicate less than median precipitation in the entire Zacatecas state territory. For instance, SPI at 12-month time scale Sen’s slope values were -0.17 and -0.18 for the wet and dry seasons, respectively in the Semi-desert region. Thus, the evidenced trends may be having influence on the availability of surface water, groundwater levels and aquifers recharge in the near future. So, it is imperative to adjust inhabitants’ activities according to design planned climate change adaptation strategies.

scholarly journals Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann
Keyword(s):  
Air Temperature ◽  
Daily Rainfall ◽  
Climatic Conditions ◽  
Dry Season ◽  
Climate Impacts ◽  
Calling Behavior ◽  
Wet Season ◽  
Focal Species ◽  
Calling Activity ◽  
Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

scholarly journals Caractérisation à l’aide du SPI de la Sécheresse climatique dans le bassin versant de Ziz (Sud-Est, Maroc)

2018 ◽  
Vol 14 (21) ◽  
pp. 177 ◽  
Author(s):  
Radouan Mehdaoui ◽  
El-Mostafa Mili ◽  
Aziz Seghir
Keyword(s):  
Temporal Variability ◽  
Standardized Precipitation Index ◽  
Winter Season ◽  
Spatial And Temporal Variability ◽  
Drought Period ◽  
North Eastern ◽  
Edge Part ◽  
The Standardized Precipitation Index ◽  
Bassin Versant ◽  
Eastern Edge

This paper analyzes the spatial and temporal variability of drought in winter season in an arid geographical gradient located in the eastern edge part of the Moroccan High Atlas especially at the Ziz watershed. Drought period between 1975 and 2013 were analyzed using the Standardized Precipitation Index (SPI) over 12 months for a 38-year scale. The results indicate that the most important drought by intensity and duration occurred during the 1982/84, 1983/84, 2000/01, and 2004/05 periods are generalized on all stations of the basin with a minimum SPI reached -2.77 at the Taous station. The results indicate that drought in winter have been tied to the dominance of dry circulation with the exception of the frequency of thermodynamic and north-eastern disturbances which are considered unstable aerological conditions. Which occur frequently between February and April of each year for the Errachidia station, Hassan Adakhil Dam, Foum Zaabal, Tillicht, M'Zizl, Arfoud and Taouz.

scholarly journals Spatial and temporal variability of canopy cover and understory light in a Cerrado of Southern Brazil

2010 ◽  
Vol 70 (1) ◽  
pp. 19-24 ◽  
Author(s):  
JP. Lemos-Filho ◽  
CFA. Barros ◽  
GPM. Dantas ◽  
LG. Dias ◽  
RS. Mendes
Keyword(s):  
Rainy Season ◽  
Light Availability ◽  
Canopy Cover ◽  
Dry Season ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Spatial And Temporal Variability ◽  
Wet Season ◽  
Area Index ◽  
Understory Plants

Canopy cover has significant effects on the understory environment, including upon light availability for seedling growth. The aim of the present study was to verify spatial heterogeneity and seasonal changes in the canopy cover of a dense Cerrado area, and their relationship to understory photosynthetic active radiation availability. Leaf area index (LAI) values in the rainy season varied from 0.9 to 4.83, with 40% of the values ranging from 4.0 to 5.0, while in the dry season LAI varied from 0.74 to 3.3, with 53% of the values oscilating from 2.0 to 3.0. Understory light (Qi ) and the Lambert-Beer ratio (Qi/Qo) were taken around noon on sunny days (between 11:00 AM and 1:00 PM). They were also statistically different (p < 0.01) between the dry and wet seasons, with 72% of sampled points in the rainy season presenting photosynthetic photon flux density (PPFD) values lower than 250 μmol.m-2/s around noon, whereas in the dry season, most PPFD values varied from 1500 to 1817 μmol.m-2/s , thus providing high light availability for understory plants. In most of the studied sites, understory plants did not even receive enough light for 50% of their photosynthetic capacity in the wet season. In contrast during the dry season, Qi/Qo values of 0.8 to 1.0 were observed in more than 50% of the points, thereby allowing for photosynthetic light saturation. Thus, light variability around noon was higher during the dry season than in the wet season, its heterogeneity being related to spatial complexity in the canopy cover.

scholarly journals Drought cycle tracking in Hungary using Standardized Precipitation Index (SPI)

2019 ◽  
pp. 97-101 ◽  
Author(s):  
Safwan A. Mohammed ◽  
Endre Harsányi
Keyword(s):  
Climate Change ◽  
Eastern Europe ◽  
Natural Hazard ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Rainfall Data ◽  
Trend Test ◽  
Economic Sectors ◽  
Similar Vein ◽  
The Standardized Precipitation Index

 Drought is one of the natural hazard risks which badly affects both agricultural and socio-economic sectors. Hungary, which is located in Eastern Europe has been suffering from different drought cycles; therefore, the aim of this study is to analyse the rainfall data obtained from ten metrological stations (Békéscsaba, Budapest, Debrecen, Győr, Kékestető, Miskolc, Pápa, Pécs, Szeged, Siófok, Szolnok) between 1985 and 2016, by using the Standardized Precipitation Index (SPI). The results showed that 2011 was recorded as the worst drought cycle of the studied period, where the SPI ranged between -0.22 (extreme drought) in Siófok, and 0.15 (no drought) in Miskolc. In a similar vein, the study highlighted the year 2010 to be the best hydrological year, when the SPI reached 0.73 (mildly wet) on average. Interestingly, the Mann-Kendall trend test for the drought cycle showed no positive trends in the study area. Finally, more investigation should be conducted into the climate change spatial drought cycle in Europe.

scholarly journals Pemetaan Indek Kekeringan dan Sebaran Titik Hotspot Daerah Potensi Kebakaran Hutan dan Lahan di Propinsi Riau

2018 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Yotta Autika ◽  
Aras Mulyadi ◽  
Yusni Ikhwan Siregar
Keyword(s):  
Land Use ◽  
Standardized Precipitation Index ◽  
Meteorological Drought ◽  
Dry Season ◽  
Wet Season ◽  
Index Method ◽  
Spi Index ◽  
Maximum Duration ◽  
Relationship Of ◽  
The Relationship

Riau is one of the most vulnerable provinces to forest and land fires in Indonesia. The potency for forest and land fires is inseparable from the presence of peatlands and exacerbated by drought. The purpose of this research is to know the characteristics of meteorological drought using SPI (Standardized Precipitation Index) method and its relation with forest and peatland fire as one of disaster management effort in Riau Province. The data used in this research are monthly rainfall data from meteorology station and rainfall posts of BMKG, hotspot data from NOAA satellite, map of Forest Use Agreement (TGHK), peat land map and land use map. Analysis of drought characteristics was done by calculating monthly SPI-1 then determining the maximum duration, intensity, severity and drought exposure. Determination of the severity of the drought by weighting and suspension method was based on duration and intensity while drought exposure was done by overlaying the map of the severity of the drought with the land use map. Meanwhile, to know the potential of forest and land fires began with the selection of hotspots on peatlands and forest areas every month then created a graph of the relationship of meteorological drought with the number of hotspots. Then, to see the relationship of drought distribution to the distribution of hotspots in dry season (MK) and wet season (MH) of 2015 was done by overlaying cover the drought distribution with hotspot distribution. The result shows that drought characteristic in the most of Riau province has maximum duration around 4-6 months, dry category of intensity, high category of severity with exposure area in paddy field, field, habitation, and plantation. Then, negative SPI Index (dry condition) has potential to increase the number of hotspots otherwise positive SPI index (wet condition) leads to low occurrence of hotspot. The drought distribution in the dry season (July, August, September) of 2015 triggers the number of hotspots during drought conditions, while in wet season (April, November, December) of 2015 are dominated by normal conditions, some areas are dry and wet, resulting in lower hotspots distribution compared to the dry season.

Respective frequencies of early and late embryonic mortality in Prim’ Holstein cows under subtropical conditions

2001 ◽  
Vol 26 (2) ◽  
pp. 389-392
Author(s):  
E. Tillard ◽  
S. Nabeneza ◽  
B. Faye ◽  
P. Humblot
Keyword(s):  
Pregnancy Rate ◽  
Specific Protein ◽  
Climatic Conditions ◽  
Dry Season ◽  
Reproductive Failure ◽  
Embryonic Mortality ◽  
Holstein Cows ◽  
Wet Season ◽  
Early Embryonic Mortality ◽  
Tropical Climates

AbstractThe frequency of early and late embryonic mortality was determined following 171 inseminations performed between January and December 1998 in 6 herds located in Reunion Island. Milk was sampled 23 to 24 days after Alfor progesterone determination in cows not observed to return to oestrus after AI. Cows were also blood sampled at between 30 and 45 days post-AI to measure Pregnancy Specific Protein B. Overall pregnancy rate was 25.1% (range between herds 12.5% to 42.3%). Early embryonic mortality or fertilisation failures and late embryonic mortality occurred in 57.3% (range between herds 52.9% to 61.6%) and 17.5% (range between herds 3.8% to 33.4%) of cows inseminated, respectively. Nonpregnant cows, not detected in oestrus by Day 24 after AI were recorded to returned to oestrus, on average 66 ±9.6 days or more than 3 cycles after AI. The pregnancy rate was depressed when cows were inseminated during the wet season compared with cows inseminated during the dry season. We conclude that fertilisation failures or early embryonic mortality was the main cause of reproductive failure in inseminated cows in tropical climates. The incidence was twice that obtained in studies conducted under more temperate climatic conditions.

scholarly journals Spatiotemporal drought analysis by the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) in Sichuan Province, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Changhong Liu ◽  
Cuiping Yang ◽  
Qi Yang ◽  
Jiao Wang
Keyword(s):  
Standardized Precipitation Index ◽  
Sichuan Province ◽  
Precipitation Index ◽  
Trend Test ◽  
Linear Regression Method ◽  
Standardized Precipitation Evapotranspiration Index ◽  
Time And Space ◽  
Mountainous Regions ◽  
Drought Characteristics ◽  
The Standardized Precipitation Index

AbstractDrought refers to a meteorological disaster that causes insufficient soil moisture and damage to crop water balance due to long-term lack of precipitation. With the increasing shortage of water resources, drought has become one of the hot issues of global concern. The standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) can effectively reflect the changes in drought characteristics of different geomorphologies in Sichuan on time and space scales, to explore the difference in drought characteristics between different physiognomy types in Sichuan Province, We calculated the SPI and SPEI values based on the data of 44 meteorological stations in Sichuan Province from 1961 to 2019 and used Mann–Kendall trend test and multivariable linear regression method (MLR) to quantify the significance of the drought characteristic trends at different time and space scales. The results as follow: (1) The SPEI drought trend in plain and hilly regions was greater than that in plateau and mountain regions on all time scales (− 0.039 year−1 for 1-month in hilly, − 0.035 year−1 for 1-month in plain, − 0.14 year−1 for 1-month in plateau, − 0.026 year−1 for 1-month in mountain) and the magnitude of trend of eastern (− 4.4 to 0.1 year−1) was lager than western (− 2.1 to 2.7 year−1), means that the drought trends transfer from northwest to east. (2) The drought intensity in the western region gradually increased (0.54–1.05) and drought events mainly occurred in the southwest plateau and central mountainous regions (24–47 times), means that drought meteorological hotspots were mainly concentrated in the Sichuan basin. (3) The MLR indicated altitude (H) is not the main influencing factor that causes the spatial unevenness of precipitation in Sichuan Province, but altitude (H), temperature (T), longitude (Lo) and latitude (La) can co-determined the precipitation. The results of this study are instructive and practical for drought assessment, risk management and application decision-making in Sichuan Province, and have guiding significance for agricultural disaster prevention, mitigation and agricultural irrigation in Sichuan Province.

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