scholarly journals Study on the possibility of predicting the onset and rainfall of wet season in Yogyakarta Special Province, Indonesia

2020 ◽  
Vol 35 (2) ◽  
pp. 55
Author(s):  
Dewi Galuh Condro Kirono ◽  
Budi Salmon
Keyword(s):  
Extreme Event ◽  
Late Onset ◽  
Southern Oscillation ◽  
Flood Hazard ◽  
Onset Time ◽  
Daily Rainfall ◽  
Rainfall Anomaly ◽  
Air Pressure ◽  
Wet Season ◽  
June July

Indonesian region frequently experiences a prolonged drought and/or flood hazard One of the key factors that often triggers these Awards is the occurrence of seasonal rainfall anomaly. To minimize the possible impact of such extreme event, it is necessary to develop a model that can be applied to predict the wet season onset and wet season rainfall. This paper is a preliminary effort on this mailer. As a pilot study, Yogyakarta Special Province (DIY) has been selected for this purpose. In particular; the analysis is emphasized on the Adisucipto airport station, Yogyakarta, as it is one of the first-class climatological station in DIY which has a very good and long data required for such intention. Detail objectives of this study are to address the following three questions: (1) is it possible to predict wet season onset in Adisucipto airport station using local and regional atmospheric indicators? (2) if it is possible and the model(s) have been developed, can the model(s) be applied for predicting the onset of wet season in other parts of DIY and its surround? (3) does an early or late onset of wet season provide any indication to subsequent rainfall during the wet season? To achieve these objectives, the study requires several types of data including daily rainfall data, monthly air pressure data, Southern Oscillation Index (SO!) and Sea Surface Temperature data. Most of the data cover the period of 1976 to 2001. Methods that have been applied to meet the goals are statistical descriptive and simple liner regression analysis. The results suggest that: (I) wet season onset time in Yogyakarta can be predicted using both local and regional atmospheric factors. namely August and September SOI, and air pressure index at Adisucipto airport station in June. July and August; (2) models that have been developed for Adisucipto airport station are modest enough to be applied for predicting the onset of wet season at other location; (3) the onset of wet season cannot be used as an indicator to estimate rainfall in wet season itself.

scholarly journals Interannual and Intraseasonal Variations of the Onset and Demise of the Pre-Wet Season and the Wet Season in the Northern Northeast Brazil

2018 ◽  
Vol 33 (3) ◽  
pp. 472-484 ◽  
Author(s):  
Francisco das Chagas Vasconcelos Junior ◽  
Charles Jones ◽  
Adilson Wagner Gandu
Keyword(s):  
Late Onset ◽  
Southern Oscillation ◽  
Wave Train ◽  
South Atlantic Convergence Zone ◽  
Southeastern Brazil ◽  
Precipitation Pattern ◽  
Northeast Brazil ◽  
Tropical Atlantic ◽  
Wet Season ◽  
Sst Anomalies

Abstract The Northern Northeast Brazil (NNB) has two rainy periods, namely Pre-Wet Season (PWS) and Wet Season (WES), which are usually treated as one system. The precipitation pattern on NNB is influenced by sea surface temperature (SST) anomalies in the Atlantic and Pacific Ocean on interannual timescales particularly by the Interhemispheric Gradient of SST anomalies (IGS) and El Niño Southern Oscillation (ENSO). On intraseasonal time scales, the MJO is especially important. This study investigates the variability of the PWS/WES. The PWS is largely associated with the development of the South America Monsoon System and South Atlantic Convergence Zone (SAMS/SACZ); the onset is depicted by incursion of the SAMS/SACZ northward. Anomalous atmospheric cyclonic circulation over the southeastern Brazil along with easterlies over the northern Tropical Atlantic marks the early onset of the PWS, while easterlies over the southern Tropical Atlantic are related to late onset episodes. The demise of the PWS is significantly associated with propagation of the MJO, specifically during phases 4-5 of the MJO lifecycle. A Rossby wave train in 200-hPa geopotential height with positive anomalies over central-southern Brazil is depicted during transition between PWS and WES.

scholarly journals Changes in the wintertime hydroclimatic regime in St. John River, Maine, USA

2021 ◽  
Author(s):  
Jong-Suk Kim ◽  
Shaleen Jain ◽  
Taesam Lee
Keyword(s):  
River Basin ◽  
Large Scale ◽  
Extreme Event ◽  
Southern Oscillation ◽  
Flood Hazard ◽  
Flow Characteristics ◽  
Teleconnection Pattern ◽  
Diagnostic Study ◽  
Atmospheric Teleconnection ◽  
Weather Events

Abstract Changes in the flow regime in snowmelt- and ice-dominated rivers have important implications for navigation, flood hazard, recreation, and ecosystems. We investigated recent changes in the high flows of the St. John River basin in Maine, USA, with a view to quantify changes in high-flow characteristics, as well as extreme event estimates. The results analyzed herein demonstrate shifts in springtime streamflow as well as in emergent wintertime (January–February) streamflow over the past four decades. A Poisson-based regression approach was applied to develop a model for the diagnosis of weather–climate linkage. The sensitivity of episodic warm weather events to the negative phase of the Tropical–Northern Hemisphere (TNH) atmospheric teleconnection pattern is evident. Although a modest sample size of historical data on the weather–climate linkage imposes a limit in terms of reliability, the approach presented herein shows a modest role of the TNH pattern, in response to the warm phase of El Niño/Southern Oscillation, as one of the factors that contribute to hydroclimate variability in the St. John River basin. This diagnostic study sought to investigate the changes in the wintertime streamflow regime and the relative linkages with short-term concurrent weather events, as well as large-scale climatic linkages. This improved an understanding of hydrological extremes within a climatological context and offers new knowledge to inform water resources planning and decision-making.

Probabilistic Forecasts of the Onset of the North Australian Wet Season

2007 ◽  
Vol 135 (10) ◽  
pp. 3506-3520 ◽  
Author(s):  
Fiona Lo ◽  
Matthew C. Wheeler ◽  
Holger Meinke ◽  
Alexis Donald
Keyword(s):  
Southern Oscillation ◽  
Daily Rainfall ◽  
Sea Surface ◽  
Onset Date ◽  
Forecast Method ◽  
Wet Season ◽  
The North ◽  
Probabilistic Forecasts ◽  
Cape York ◽  
Agricultural Industries

Abstract The amount and timing of early wet-season rainfall are important for the management of many agricultural industries in north Australia. With this in mind, a wet-season onset date is defined based on the accumulation of rainfall to a predefined threshold, starting from 1 September, for each square of a 1° gridded analysis of daily rainfall across the region. Consistent with earlier studies, the interannual variability of the onset dates is shown to be well related to the immediately preceding July–August Southern Oscillation index (SOI). Based on this relationship, a forecast method using logistic regression is developed to predict the probability that onset will occur later than the climatological mean date. This method is expanded to also predict the probabilities that onset will be later than any of a range of threshold dates around the climatological mean. When assessed using cross-validated hindcasts, the skill of the predictions exceeds that of climatological forecasts in the majority of locations in north Australia, especially in the Top End region, Cape York, and central Queensland. At times of strong anomalies in the July–August SOI, the forecasts are reliably emphatic. Furthermore, predictions using tropical Pacific sea surface temperatures (SSTs) as the predictor are also tested. While short-lead (July–August predictor) forecasts are more skillful using the SOI, long-lead (May–June predictor) forecasts are more skillful using Pacific SSTs, indicative of the longer-term memory present in the ocean.

scholarly journals The influence of groundwater abstraction on interpreting climate controls and extreme recharge events from well hydrographs in semi-arid South Africa

2021 ◽  
Author(s):  
James P. R. Sorensen ◽  
Jeff Davies ◽  
Girma Y. Ebrahim ◽  
John Lindle ◽  
Ben P. Marchant ◽  
...  
Keyword(s):  
South Africa ◽  
Extreme Event ◽  
Southern Oscillation ◽  
Hierarchical Cluster ◽  
Sub Saharan Africa ◽  
Small Scale ◽  
Groundwater Abstraction ◽  
Wet Season ◽  
Sub Saharan ◽  
Semi Arid

AbstractThere is a scarcity of long-term groundwater hydrographs from sub-Saharan Africa to investigate groundwater sustainability, processes and controls. This paper presents an analysis of 21 hydrographs from semi-arid South Africa. Hydrographs from 1980 to 2000 were converted to standardised groundwater level indices and rationalised into four types (C1–C4) using hierarchical cluster analysis. Mean hydrographs for each type were cross-correlated with standardised precipitation and streamflow indices. Relationships with the El Niño–Southern Oscillation (ENSO) were also investigated. The four hydrograph types show a transition of autocorrelation over increasing timescales and increasingly subdued responses to rainfall. Type C1 strongly relates to rainfall, responding in most years, whereas C4 notably responds to only a single extreme event in 2000 and has limited relationship with rainfall. Types C2, C3 and C4 have stronger statistical relationships with standardised streamflow than standardised rainfall. C3 and C4 changes are significantly (p < 0.05) correlated to the mean wet season ENSO anomaly, indicating a tendency for substantial or minimal recharge to occur during extreme negative and positive ENSO years, respectively. The range of different hydrograph types, sometimes within only a few kilometres of each other, appears to be a result of abstraction interference and cannot be confidently attributed to variations in climate or hydrogeological setting. It is possible that high groundwater abstraction near C3/C4 sites masks frequent small-scale recharge events observed at C1/C2 sites, resulting in extreme events associated with negative ENSO years being more visible in the time series.

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 Biomass Burning and Water Balance Dynamics in the Lake Chad Basin in Africa

Earth ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 340-356
Author(s):  
Forrest W. Black ◽  
Jejung Lee ◽  
Charles M. Ichoku ◽  
Luke Ellison ◽  
Charles K. Gatebe ◽  
...  
Keyword(s):  
Water Balance ◽  
Biomass Burning ◽  
Water Cycle ◽  
Potential Evapotranspiration ◽  
Southern Oscillation ◽  
Wet Season ◽  
Lake Chad ◽  
Chad Basin ◽  
Lake Chad Basin ◽  
Logone Catchment

The present study investigated the effect of biomass burning on the water cycle using a case study of the Chari–Logone Catchment of the Lake Chad Basin (LCB). The Chari–Logone catchment was selected because it supplies over 90% of the water input to the lake, which is the largest basin in central Africa. Two water balance simulations, one considering burning and one without, were compared from the years 2003 to 2011. For a more comprehensive assessment of the effects of burning, albedo change, which has been shown to have a significant impact on a number of environmental factors, was used as a model input for calculating potential evapotranspiration (ET). Analysis of the burning scenario showed that burning grassland, which comprises almost 75% of the total Chari–Logone land cover, causes increased ET and runoff during the dry season (November–March). Recent studies have demonstrated that there is an increasing trend in the LCB of converting shrubland, grassland, and wetlands to cropland. This change from grassland to cropland has the potential to decrease the amount of water available to water bodies during the winter. All vegetative classes in a burning scenario showed a decrease in ET during the wet season. Although a decrease in annual precipitation in global circulation processes such as the El Niño Southern Oscillation would cause droughts and induce wildfires in the Sahel, the present study shows that a decrease in ET by the human-induced burning would cause a severe decrease in precipitation as well.

Road Construction and Rainfall as Landslide Triggers in the Rio Lucma Catchment, Eastern Cordillera Blanca, Peru

2021 ◽  
Author(s):  
Lorena Abad ◽  
Daniel Hölbling ◽  
Adam Emmer
Keyword(s):  
Satellite Imagery ◽  
Southern Oscillation ◽  
Road Construction ◽  
Automated Analysis ◽  
Rainfall Data ◽  
Construction Work ◽  
Visual Interpretation ◽  
Wet Season ◽  
Cordillera Blanca ◽  
The Road

&lt;p&gt;Extensive road construction works were recently undertaken in the remote eastern part of the Peruvian Cordillera Blanca, aiming at better connecting isolated mountain communities with regional administrative centres. In the R&amp;#237;o Lucma catchment, approximately 47 km of roads were constructed between 2015 and 2018, triggering several landslides that affected an approximate area of 32 ha. We identified and characterised these landslides by combining field mapping, visual interpretation and semi-automated analysis of satellite imagery (PlanetScope and RapidEye-2), and analysis of rainfall data from two stations of the Servicio Nacional de Meteorolog&amp;#237;a e Hidrolog&amp;#237;a del Per&amp;#250; (SENAMHI). We investigated in detail three specific areas of interest, where we identified, delineated, and described 56 landslides. We classified the landslides in relation to their position to the road as: landslides downslope the roads (48.2%), complex landslides crossing the roads (46.4 %), and landslides onto the road (5.3%). According to the type of movement, we found that the slide-type movement (60.7%) prevails over the flow-type movement (39.3%). Timewise, we found that 75% of landslides were observed on satellite imagery simultaneously with road construction work, while the remaining 25% were identified between one week and seven months after the roads had been constructed. We analysed lagged cumulative rainfall data against the occurrence of these subsequent landslides, determining that a two-week rainfall accumulation can act as triggering factor of landslides after road construction work. In general, 51% of the landslides were observed during the wet season (November to April) while 41.1% occurred during El Ni&amp;#241;o&amp;#8211;Southern Oscillation (ENSO) strong cool phase or &amp;#8220;La Ni&amp;#241;a&amp;#8221; period. We observed that the majority of mapped landslides were directly (e.g., landslides resulting from slope undercutting) or indirectly associated with road constructions (e.g., rainfall-induced landslides resulting from a combination of extreme precipitation over slopes with decreased stability) and that the road constructions also may set preconditions for subsequent rainfall-triggered landslides.&lt;/p&gt;

Anomalies of continental precipitation associated with El Niño Southern Oscillation: the role of moisture contribution from oceanic and terrestrial sources 

2021 ◽  
Author(s):  
Rogert Sorí ◽  
Raquel Nieto ◽  
Margarida L.R. Liberato ◽  
Luis Gimeno
Keyword(s):  
South America ◽  
Southern Oscillation ◽  
The United States ◽  
Precipitation Pattern ◽  
Two Phase ◽  
The North ◽  
Terrestrial Origin ◽  
Precipitation Anomalies ◽  
June July

&lt;p&gt;The regional and global precipitation pattern is highly modulated by the influence of El Ni&amp;#241;o Southern Oscillation (ENSO), which is considered the most important mode of climate variability on the planet. In this study was investigated the asymmetry of the continental precipitation anomalies during El Ni&amp;#241;o and La Ni&amp;#241;a. To do it, a Lagrangian approach already validated was used to determine the proportion of the total Lagrangian precipitation that is of oceanic and terrestrial origin. During both, El Ni&amp;#241;o and La Ni&amp;#241;a, the Lagrangian precipitation in regions such as the northeast of South America, the east and west coast of North America, Europe, the south of West Africa, Southeast Asia, and Oceania is generally determined by the oceanic component of the precipitation, while that from terrestrial origin provides a major percentage of the average Lagrangian precipitation towards the interior of the continents. The role of the moisture contribution to precipitation from terrestrial and oceanic origin was evaluated in regions with statistically significant precipitation anomalies during El Ni&amp;#241;o and La Ni&amp;#241;a. Two-phase asymmetric behavior of the precipitation was found in regions such the northeast of South America, South Africa, the north of Mexico, and southeast of the United States, etc. principally for December-January-February and June-July-August. For some of these regions was also calculated the anomalies of the precipitation from other datasets to confirm the changes. Besides, for these regions was calculated the anomaly of the Lagrangian precipitation, which agrees in all the cases with the precipitation change. For these regions, it was determined which component of the Lagrangian precipitation, whether oceanic or terrestrial, controlled the precipitation anomalies. A schematic figure represents the extent of the most important seasonal oceanic and terrestrial sources for each subregion during El Ni&amp;#241;o and La Ni&amp;#241;a.&lt;/p&gt;

scholarly journals Uncertainties in the Annual Cycle of Rainfall Characteristics over West Africa in CMIP5 Models

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 216
Author(s):  
Magatte Sow ◽  
Moussa Diakhaté ◽  
Ross D. Dixon ◽  
Françoise Guichard ◽  
Diarra Dieng ◽  
...  
Keyword(s):  
West Africa ◽  
Annual Cycle ◽  
Late Onset ◽  
Daily Rainfall ◽  
Cmip5 Models ◽  
Monthly Precipitation ◽  
Strongly Coupled ◽  
Precipitation Estimates ◽  
Latitudinal Position ◽  
Systematic Biases

We analyse uncertainties associated with the main features of the annual cycle of West African rainfall (amplitude, timing, duration) in 15 CMIP5 simulations over the Sahelian and Guinean regions with satellite daily precipitation estimates. The annual cycle of indices based on daily rainfall such as the frequency and the intensity of wet days, the consecutive dry (CDD) and wet (CWD) days, the 95th percentile of daily rainfall (R95), have been assessed. Over both regions, satellite datasets provide more consistent results on the annual cycle of monthly precipitation than on higher-frequency rainfall indices, especially over the Guinean region. By contrast, CMIP5 simulations display much higher uncertainties in both the mean precipitation climatology and higher-frequency indices. Over both regions, most of them overestimate the frequency of wet days. Over the Guinean region, the difficulty of models to represent the bimodality of the annual cycle of precipitation involves systematic biases in the frequency of wet days. Likewise, we found strong uncertainties in the simulation of the CWD and the CDD over both areas. Finally, models generally provide too early (late) onset dates over the Sahel (the Guinean region) and overestimate rainfall during the early and late monsoon phases. These errors are strongly coupled with errors in the latitudinal position of the ITCZ and do not compensate at the annual scale or when considering West Africa as a whole.

scholarly journals Accurate Quantification of Seasonal Rainfall and Associated Climate–Wildfire Relationships

2010 ◽  
Vol 49 (12) ◽  
pp. 2559-2573 ◽  
Author(s):  
Matthew G. Slocum ◽  
William J. Platt ◽  
Brian Beckage ◽  
Steve L. Orzell ◽  
Wayne Taylor
Keyword(s):  
Daily Rainfall ◽  
Seasonal Rainfall ◽  
Wet Season ◽  
Rainfall Characteristics ◽  
Central Florida ◽  
South Central ◽  
Multiple Regression Technique ◽  
Precise Quantification ◽  
Rainfall Anomalies ◽  
Force Range

Abstract Wildfires are often governed by rapid changes in seasonal rainfall. Therefore, measuring seasonal rainfall on a temporally finescale should facilitate the prediction of wildfire regimes. To explore this hypothesis, daily rainfall data over a 58-yr period (1950–2007) in south-central Florida were transformed into cumulative rainfall anomalies (CRAs). This transformation allowed precise estimation of onset dates and durations of the dry and wet seasons, as well as a number of other variables characterizing seasonal rainfall. These variables were compared with parameters that describe ENSO and a wildfire regime in the region (at the Avon Park Air Force Range). Onset dates and durations were found to be highly variable among years, with standard deviations ranging from 27 to 41 days. Rainfall during the two seasons was distinctive, with the dry season having half as much as the wet season despite being nearly 2 times as long. The precise quantification of seasonal rainfall led to strong statistical models describing linkages between climate and wildfires: a multiple-regression technique relating the area burned with the seasonal rainfall characteristics had an of 0.61, and a similar analysis examining the number of wildfires had an of 0.56. Moreover, the CRA approach was effective in outlining how seasonal rainfall was associated with ENSO, particularly during the strongest and most unusual events (e.g., El Niño of 1997/98). Overall, the results presented here show that using CRAs helped to define the linkages among seasonality, ENSO, and wildfires in south-central Florida, and they suggest that this approach can be used in other fire-prone ecosystems.

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