The impact of the 1997/98 El-Nino rains on the water quality of lake Naivasha, Kenya

2002 ◽  
Vol 7 (1) ◽  
Author(s):  
K. S. Makhanu ◽  
E. C. Mwachiro ◽  
C. K. Kamau ◽  
A. Gachanja
2021 ◽  
Vol 4 (1) ◽  
pp. 72
Author(s):  
Ida Bagus Mandhara Brasika

The aim of this research is to understand the impact of El Nino Modoki into Indonesian precipitation and how ensemble models can simulate this changing. Ensemble model has been recognized as a method to improve the quality of model and/or prediction of climate phenomenon. Every model has their own algorithm which causes strength and weakness in many aspects. Ensemble will improve the quality of simulation while reducing the weakness. However, the combination of models for ensembles is differ for each event and/or location. Here we utilize the Squared Error Skill Score (SESS) method to examine each model quality and to compare the ensemble model with the single model. El Nino Modoki is a unique phenomenon. It remains debatable amongst scientists, many features of this phenomenon are unfold. So, it is important to find out how El Nino Modoki has changed precipitation over Indonesia. To verify the changing precipitation, the composite of precipitation on El Nino Modoki Year is divided with the composite of all years. Last, validating ensemble model with Satellite-gauge precipitation dataset. El Nino Modoki decreases precipitation in most of Indonesian regions. The ensemble, while statistically promising, has failed to simulate precipitation in some region.


2020 ◽  
Author(s):  
Asnake Ararsa Irenso ◽  
Shiferaw Letta ◽  
Addisu Sebsibe ◽  
Abiyot Asfaw ◽  
Gudina Egata ◽  
...  

Abstract Background: Ethiopia is affected by recurrent drought and food insecurity crises including from El Niño, the climatic change that lasted from mid-2014 through 2016 and caused the failure of the rainy seasons in eastern Ethiopia. The event is expected to have a detrimental effect on the already suboptimal complementary feeding practices. However, there is a lack of research on how climatic events affect child feeding. Hence, the study was intended to explore how El Niño influenced the complementary feeding practices and experiences of the food-insecure community of eastern Ethiopia from March to September 2016.Methods: This study was an exploratory qualitative study that used a phenomenological approach. The study was conducted in the food-insecure setting of Gale Mirga kebele of Kersa district. The study involved 11 focus group discussion (FGD) comprising a total of 76 participants, including three FGDs with mothers, three FGDs with Health Development Army leaders (HDA); two FGDs with fathers, two FGDs with traditional birth attendants, and one FGD with religious leaders. The Atlas.ti software was used for coding and thematic analysis.Results: El Niño aggravated failed crop and livestock loss were reported to directly reduce the quantity and quality of food available to feed young children, resulting in more frequent skipping of meals, less animal protein sources and over-reliance of cereal-based food. The impact of El Nino on livelihoods often resulted in both parents working away from home with child feeding delegated to older children or other family members. Maternal absence from home was a barrier to participation in community-based nutrition activities. Short birth spacing and low fathers’ involvement in feeding also reduced the time available to mothers to devote to child feeding.Conclusions: The maternal suboptimal time allocation to child feeding is central to the poor complementary feeding practices in El Niño stricken food-insecure settings of Eastern Ethiopia. The women should be supported with climate-resilient livelihoods options in their villages, thus allowing them both to feed their children and attend nutrition education sessions with HDA. Such sessions should focus on food processing demonstrations to improve the nutritional quality of plant-based complementary foods.


2021 ◽  
Vol 13 (9) ◽  
pp. 1683
Author(s):  
Nandini Menon ◽  
Grinson George ◽  
Rajamohananpillai Ranith ◽  
Velakandy Sajin ◽  
Shreya Murali ◽  
...  

Turbidity and water colour are two easily measurable properties used to monitor pollution. Here, we highlight the utility of a low-cost device—3D printed, hand-held Mini Secchi disk (3DMSD) with Forel-Ule (FU) colour scale sticker on its outer casing—in combination with a mobile phone application (‘TurbAqua’) that was provided to laymen for assessing the water quality of a shallow lake region after demolition of four high-rise buildings on the shores of the lake. The demolition of the buildings in January 2020 on the banks of a tropical estuary—Vembanad Lake (a Ramsar site) in southern India—for violation of Indian Coastal Regulation Zone norms created public uproar, owing to the consequences of subsequent air and water pollution. Measurements of Secchi depth and water colour using the 3DMSD along with measurements of other important water quality variables such as temperature, salinity, pH, and dissolved oxygen (DO) using portable instruments were taken for a duration of five weeks after the demolition to assess the changes in water quality. Paired t-test analyses of variations in water quality variables between the second week of demolition and consecutive weeks up to the fifth week showed that there were significant increases in pH, dissolved oxygen, and Secchi depth over time, i.e., the impact of demolition waste on the Vembanad Lake water quality was found to be relatively short-lived, with water clarity, colour, and DO returning to levels typical of that period of year within 4–5 weeks. With increasing duration after demolition, there was a general decrease in the FU colour index to 17 at most stations, but it did not drop to 15 or below, i.e., towards green or blue colour indicating clearer waters, during the sampling period. There was no significant change in salinity from the second week to the fifth week after demolition, suggesting little influence of other factors (e.g., precipitation or changes in tidal currents) on the inferred impact of demolition waste. Comparison with pre-demolition conditions in the previous year (2019) showed that the relative changes in DO, Secchi depth, and pH were very high in 2020, clearly depicting the impact of demolition waste on the water quality of the lake. Match-ups of the turbidity of the water column immediately before and after the demolition using Sentinel 2 data were in good agreement with the in situ data collected. Our study highlights the power of citizen science tools in monitoring lakes and managing water resources and articulates how these activities provide support to Sustainable Development Goal (SDG) targets on Health (Goal 3), Water quality (Goal 6), and Life under the water (Goal 14).


2010 ◽  
Vol 67 (9) ◽  
pp. 2854-2870 ◽  
Author(s):  
Tingting Gong ◽  
Steven B. Feldstein ◽  
Dehai Luo

Abstract This study examines the relationship between intraseasonal southern annular mode (SAM) events and the El Niño–Southern Oscillation (ENSO) using daily 40-yr ECMWF Re-Analysis (ERA-40) data. The data coverage spans the years 1979–2002, for the austral spring and summer seasons. The focus of this study is on the question of why positive SAM events dominate during La Niña and negative SAM events during El Niño. A composite analysis is performed on the zonal-mean zonal wind, Eliassen–Palm fluxes, and two diagnostic variables: the meridional potential vorticity gradient, a zonal-mean quantity that is used to estimate the likelihood of wave breaking, and the wave breaking index (WBI), which is used to evaluate the strength of the wave breaking. The results of this investigation suggest that the background zonal-mean flow associated with La Niña (El Niño) is preconditioned for strong (weak) anticyclonic wave breaking on the equatorward side of the eddy-driven jet, the type of wave breaking that is found to drive positive (negative) SAM events. A probability density function analysis of the WBI, for both La Niña and El Niño, indicates that strong anticyclonic wave breaking takes place much more frequently during La Niña and weak anticyclonic wave breaking during El Niño. It is suggested that these wave breaking characteristics, and their dependency on the background flow, can explain the strong preference for SAM events of one phase during ENSO. The analysis also shows that austral spring SAM events that coincide with ENSO are preceded by strong stratospheric SAM anomalies and then are followed by a prolonged period of wave breaking that lasts for approximately 30 days. These findings suggest that the ENSO background flow also plays a role in the excitation of stratospheric SAM anomalies and that the presence of these stratospheric SAM anomalies in turn excites and then maintains the tropospheric SAM anomalies via a positive eddy feedback.


2021 ◽  
Vol 9 (4) ◽  
pp. 377
Author(s):  
Dong Eun Lee ◽  
Jaehee Kim ◽  
Yujin Heo ◽  
Hyunjin Kang ◽  
Eun Young Lee

The impact of climatic variability in atmospheric conditions on coastal environments accompanies adjustments in both the frequency and intensity of coastal storm surge events. The top winter season daily maximum sea level height events at 20 tidal stations around South Korea were examined to assess such impact of winter extratropical cyclone variability. As the investigation focusses on the most extreme sea level events, the impact of climate change is found to be invisible. It is revealed that the measures of extreme sea level events—frequency and intensity—do not correlate with the local sea surface temperature anomalies. Meanwhile, the frequency of winter extreme events exhibits a clear association with the concurrent climatic indices. It was determined that the annual frequency of the all-time top 5% winter daily maximum sea level events significantly and positively correlates with the NINO3.4 and Pacific Decadal Oscillation (PDO) indices at the majority of the 20 tidal stations. Hence, this indicates an increase in extreme event frequency and intensity, despite localized temperature cooling. This contradicts the expectation of increases in local extreme sea level events due to thermal expansion and global climate change. During El Nino, it is suggested that northward shifts of winter storm tracks associated with El Nino occur, disturbing the sea level around Korea more often. The current dominance of interannual storm track shifts, due to climate variability, over the impact of slow rise on the winter extreme sea level events, implies that coastal extreme sea level events will change through changes in the mechanical drivers rather than thermal expansion. The major storm tracks are predicted to continue shifting northward. The winter extreme sea level events in the midlatitude coastal region might not go through a monotonic change. They are expected to occur more often and more intensively in the near future, but might not continue doing so when northward shifting storm tracks move away from the marginal seas around Korea, as is predicted by the end of the century.


2021 ◽  
Vol 27 (1) ◽  
Author(s):  
MANOJ KUMAR SHUKLA

Present study points out the impact of Lockdown on the health of the Yamuna river at Delhi stretch by comparing prelockdown and Post-lockdown period by studying the reports of pollution monitoring agencies. Delhi segment of the Yamuna is highly polluted, where alongwith domestic sewage a huge quantity of industrial waste is being discharged continuously without proper treatment. Pre lockdown (March 2020) water quality parameters at three sampling stations named as Palla, Nizammuddin Bridge and Okhla barrage U/s in Delhi were, pH were 8.7, 7.3 and 7.2, DO were 17.1 mg/L, not detected in later two sites, BOD were 7.9 mg/L, 57 mg/L and 27 mg/L and COD were 28 mg/L, 90 mg/L and 95 mg/L respectively and postlockdown period (April 2020) the pH was 7.8, 7.2 and 7.1, DO was 8.3 mg/L, 2.4 mg/L and 1.2 mg/L BOD was 2 mg/L, 5.6 mg/ L and 6.1 mg/L and COD were 6 mg/L, 16 mg/L and 18 mg/L respectively. The study of these parameters at three sampling stations reveals that the lack of industrial pollutants discharging due to nationwide lockdown for COVID-19 pandemic had positive effect on water quality of this river. Water quality could be maintained by planned establishment of industries and setup of ETP with without gap between generation and treatment.


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