scholarly journals Examining the Value of Global Seasonal Reference Evapotranspiration Forecasts to Support FEWS NET’s Food Insecurity Outlooks

2017 ◽  
Vol 56 (11) ◽  
pp. 2941-2949 ◽  
Author(s):  
Shraddhanand Shukla ◽  
Daniel McEvoy ◽  
Mike Hobbins ◽  
Greg Husak ◽  
Justin Huntington ◽  
...  
Keyword(s):  
Food Insecurity ◽  
Central Asia ◽  
East Africa ◽  
Central America ◽  
Southern Africa ◽  
Early Warning ◽  
Reference Evapotranspiration ◽  
Dry Season ◽  
Wet Season ◽  
Skill Evaluation

AbstractThe Famine Early Warning Systems Network (FEWS NET) team provides food insecurity outlooks for several developing countries in Africa, central Asia, and Central America. This study describes development of a new global reference evapotranspiration (ET0) seasonal reforecast and skill evaluation with a particular emphasis on the potential use of this dataset by FEWS NET to support food insecurity early warning. The ET0 reforecasts span the 1982–2009 period and are calculated following the American Society for Civil Engineers formulation of the Penman–Monteith method driven by seasonal climate forecasts of monthly mean temperature, humidity, wind speed, and solar radiation from the National Centers for Environmental Prediction CFSv2 model and the National Aeronautics and Space Administration GEOS-5 model. The skill evaluation, using deterministic and probabilistic scores, focuses on the December–February (DJF), March–May (MAM), June–August (JJA), and September–November seasons. The results indicate that ET0 forecasts are a promising tool for early warning of drought and food insecurity. Globally, the regions where forecasts are most skillful (correlation > 0.35 at leads of 2 months) include the western United States, northern parts of South America, parts of the Sahel region, and southern Africa. The FEWS NET regions where forecasts are most skillful (correlation > 0.35 at lead 3) include northern sub-Saharan Africa (DJF; dry season), Central America (DJF; dry season), parts of East Africa (JJA; wet season), southern Africa (JJA; dry season), and central Asia (MAM; wet season). A case study over parts of East Africa for the JJA season shows that ET0 forecasts in combination with the precipitation forecasts would have provided early warning of recent severe drought events (e.g., in 2002, 2004, 2009) that contributed to substantial food insecurity in the region.

The efficacy of seasonal terrestrial water storage forecasts for predicting vegetation activity over Africa

2021 ◽  
Author(s):  
Benjamin I Cook ◽  
Kimberly Slinski ◽  
Christa Peters-Lidard ◽  
Amy McNally ◽  
Kristi Arsenault ◽  
...  
Keyword(s):  
Regression Model ◽  
Southern Africa ◽  
Water Storage ◽  
Dry Season ◽  
Forecast Skill ◽  
Terrestrial Water Storage ◽  
Wet Season ◽  
Area Index ◽  
Vegetation Activity ◽  
Terrestrial Water

AbstractTerrestrial water storage (TWS) provides important information on terrestrial hydroclimate and may have value for seasonal forecasting because of its strong persistence. We use the NASA Hydrological Forecast and Analysis System (NHyFAS) to investigate TWS forecast skill over Africa and assess its value for predicting vegetation activity from satellite estimates of leaf area index (LAI). Forecast skill is high over East and Southern Africa, extending up to 3–6 months in some cases, with more modest skill over West Africa. Highest skill generally occurs during the dry season or beginning of the wet season when TWS anomalies from the previous wet season are most likely to carry forward in time. In East Africa, this occurs prior to and during the transition into the spring “Long Rains” from January–March, while in Southern Africa this period of highest skill starts at the beginning of the dry season in April and extends through to the start of the wet season in October. TWS is highly and positively correlated with LAI, and a logistic regression model shows high cross-validation skill in predicting above or below normal LAI using TWS. Combining the LAI regression model with the NHyFAS forecasts, 1-month lead LAI predictions have high accuracy over East and Southern Africa, with reduced but significant skill at 3-month leads over smaller sub-regions. This highlights the potential value of TWS as an additional source of information for seasonal forecasts over Africa, with direct applications to some of the most vulnerable agricultural regions on the continent.

scholarly journals Governance of Groundwater Resources in Transboundary Aquifers (GGRETA) project - Overview Brochure

2017 ◽  
Author(s):  
Chloé Meyer
Keyword(s):  
Central Asia ◽  
Case Studies ◽  
Central America ◽  
Southern Africa ◽  
Groundwater Resources ◽  
Phase 1 ◽  
Transboundary Aquifers ◽  
Assessment Activities

This brochure summarises activities and results of phase 1 (2013-2015) of the GGRETA project, in particular by presenting the picture emerging from the assessment activities of the 3 case studies (Stampriet Aquifer in Southern Africa, Trifinio Aquifer in Central America and Pretashkent Aquifer in Central Asia). Governance Groundwater Transboundary

scholarly journals Improving early warning of drought-driven food insecurity in Southern Africa using operational hydrological monitoring and forecasting products

2019 ◽  
Author(s):  
Shraddhanand Shukla ◽  
Kristi R. Arsenault ◽  
Abheera Hazra ◽  
Christa Peters-Lidard ◽  
Randal D. Koster ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Food Insecurity ◽  
Crop Yield ◽  
Southern Africa ◽  
Early Warning ◽  
Crop Yields ◽  
Severe Drought ◽  
Drought Event ◽  
Antecedent Soil Moisture ◽  
Monitoring And Forecasting

Abstract. The region of southern Africa (SA) has a fragile food economy and is vulnerable to frequent droughts. In 2015–2016, an El Niño-driven drought resulted in major maize production shortfalls, food price increases, and livelihood disruptions that pushed 29 million people into severe food insecurity. Interventions to mitigate food insecurity impacts require early warning of droughts – preferably as early as possible before the harvest season (typically, starting in April) and lean season (typically, starting in November). Hydrologic monitoring and forecasting systems provide a unique opportunity to support early warning efforts, since they can provide regular updates on available rootzone soil moisture (RZSM), a critical variable for crop yield, and provide forecasts of RZSM by combining the estimates of antecedent soil moisture conditions with climate forecasts. For SA, this study documents the predictive capabilities of a recently developed NASA Hydrological Forecasting and Analysis System (NHyFAS). The NHyFAS system's ability to forecast and monitor the 2015/2016 drought event is evaluated. The system's capacity to explain interannual variations in regional crop yield and identify below-normal crop yield events is also evaluated. Results show that the NHyFAS products would have identified the regional severe drought event, which peaked during December–February of 2015/2016, at least as early as 1 November 2015. Next, it is shown that February RZSM forecasts produced as early as 1 November (4–5 months before the start of harvest and about a year before the start of the next lean season) correlate fairly well with regional crop yields (r = 0.49). The February RZSM monitoring product, available in early March, correlates with the regional crop yield with higher skill (r = 0.79). It is also found that when the February RZSM forecast produced on November 1 is indicated to be in the lowest tercile, the detrended regional crop yield is below normal about two-thirds (significance level ~ 86 %) of the time. Furthermore, when the February RZSM monitoring product (available in early March) indicates a lowest tercile value, the crop yield is always below normal, at least over the sample years considered. These results indicate that the NHyFAS products can effectively support food insecurity early warning in the SA region.

scholarly journals Tracking the water fingerprints of Cocos Island: a stable isotope analysis of precipitation, surface water, and groundwater

2016 ◽  
Vol 64 (1) ◽  
pp. 105 ◽  
Author(s):  
José L. Corrales ◽  
Ricardo Sánchez-Murillo ◽  
Germain Esquivel-Hernández ◽  
Esteban Herrera ◽  
Jan Boll
Keyword(s):  
Costa Rica ◽  
Surface Water ◽  
Stable Isotope ◽  
Isotopic Composition ◽  
Central America ◽  
Dry Season ◽  
Wet Season ◽  
Surface Water And Groundwater ◽  
Cocos Island ◽  
Isotopic Characterization

<p>The use of stable isotopes of water, both <span>δ</span><sup>2</sup>H and <span>δ</span><sup>18</sup>O has provided novel insights in hydrological studies, ecological applications, understanding climate variability, and reconstructing paleoclimate. However, information on the stable isotope composition of water in tropical marine island environments is normally scarce within the Central America Isthmus. Here, we present the first isotopic characterization of precipitation, surface water, and groundwater at Cocos Island, Costa Rica within the eastern tropical Pacific Ocean region. Our results show that the Cocos Island MWL can be described as: <span>δ</span><sup>2</sup>H=8.39·<span>δ</span><sup>18</sup>O+13.3; r<sup>2</sup>=0.98 (n=29). Dry season rainfall events ranged from -4.9 ‰ <span>δ</span><sup>18</sup>O up to -2.4 ‰ <span>δ</span><sup>18</sup>O with a mean <em>d-</em>excess of 13.2 ‰. By the beginning of May, the Intertropical Convergence Zone reaches Costa Rica resulting in a notable depletion in isotope ratios (up to -10.4 ‰ <span>δ</span><sup>18</sup>O and -76.2 ‰ <span>δ</span><sup>2</sup>H). During the wet season, <span>δ</span><sup>18</sup>O composition averaged -6.1 ‰ <span>δ</span><sup>18</sup>O and -38.5 ‰ <span>δ</span><sup>2</sup>H with a mean <em>d-</em>excess of 9.9 ‰. HYSPLIT air mass back trajectories indicate a strong influence on the origin of precipitation of two main moisture transport mechanisms, the northeasterly (January-May) and southwesterly (May-November) trade winds. Small seasonal variations were observed in the isotopic composition of surface water throughout the year with mean values ranging from -3.9 ‰ <span>δ</span><sup>18</sup>O (dry season, n=19) up to -4.8 ‰ <span>δ</span><sup>18</sup>O (wet season, n=13). Groundwater samples exhibited a similar trend with more depleted composition during the wet season (-5.2 ‰ <span>δ</span><sup>18</sup>O and -29.8 ‰ <span>δ</span><sup>2</sup>H). Overall, the marine isotopic composition measured in meteoric water at Cocos Island serves to better delineate the isotopic contribution of Pacific moisture towards the Central America Isthmus. It also provides a valuable isotopic reference to discriminate from orographic distillation and Caribbean enriched rainfall inputs in continental studies.</p><div> </div>

scholarly journals Future Changes in Wet and Dry Season Characteristics in CMIP5 and CMIP6 simulations

2021 ◽  
Author(s):  
Caroline M. Wainwright ◽  
Emily Black ◽  
Richard P. Allan
Keyword(s):  
Climate Change ◽  
South America ◽  
West Africa ◽  
Southern Africa ◽  
Dry Season ◽  
Maximum Temperature ◽  
Wet Season ◽  
Dry Spells ◽  
Dry Spell ◽  
Spell Length

AbstractClimate change will result in more dry days and longer dry spells, however, the resulting impacts on crop growth depend on the timing of these longer dry spells in the annual cycle. Using an ensemble of Coupled Model Intercomparison Project Phase 5 and Phase 6 (CMIP5 and CMIP6) simulations, and a range of emission scenarios, here we examine changes in wet and dry spell characteristics under future climate change across the extended tropics in wet and dry seasons separately. Delays in the wet seasons by up to two weeks are projected by 2070-2099 across South America, Southern Africa, West Africa and the Sahel. An increase in both mean and maximum dry spell length during the dry season is found across Central and South America, Southern Africa and Australia, with a reduction in dry season rainfall also found in these regions. Mean dry season dry spell lengths increase by 5-10 days over north-east South America and south-west Africa. However, changes in dry spell length during the wet season are much smaller across the tropics with limited model consensus. Mean dry season maximum temperature increases are found to be up to 3°C higher than mean wet season maximum temperature increases over South America, Southern Africa and parts of Asia. Longer dry spells, fewer wet days, and higher temperatures during the dry season may lead to increasing dry season aridity, and have detrimental consequences for perennial crops.

scholarly journals Governance of Groundwater Resources in Transboundary Aquifers (GGRETA) project - Overview Brochure

2017 ◽  
Author(s):  
Marina Rubio
Keyword(s):  
Central Asia ◽  
Case Studies ◽  
Central America ◽  
Southern Africa ◽  
Groundwater Resources ◽  
Phase 1 ◽  
Transboundary Aquifers ◽  
Assessment Activities

This brochure summarises activities and results of phase 1 (2013-2015) of the GGRETA project, in particular by presenting the picture emerging from the assessment activities of the 3 case studies (Stampriet Aquifer in Southern Africa, Trifinio Aquifer in Central America and Pretashkent Aquifer in Central Asia). Governance Groundwater Transboundary

Notes on the Bionomics of Anopheles gambiae and A. funestus in East Africa

1948 ◽  
Vol 39 (3) ◽  
pp. 453-465 ◽  
Author(s):  
K. S. Hocking ◽  
D. G. MacInnes
Keyword(s):  
Anopheles Gambiae ◽  
East Africa ◽  
Blood Meal ◽  
Dry Season ◽  
Egg Laying ◽  
Wet Season ◽  
Rate Of Development ◽  
Mean Temperature ◽  
The Mean

Females of both A. gambiae and A. funestus were found to enter buildings throughout the night, but more A. gambiae entered between 1 and 4 a.m. and more A. funestus just before dawn. Males of both species entered only just before dawn.The rate of development of the ovaries was studied in individual mosquitos isolated in cages in the laboratory. The mean period between egg layings at a mean temperature of 25·5°C. was about 4¾ days in both species.It was found that females of A. gambiae and A. funestus did not normally spend more than 24 hours in any one hut; but that they rested outside buildings during the day time only when newly emerged and just before and just after egg-laying.Observations were made on the feeding and oviposition habits. It was found that females of both species would sometimes feed daily, whereas digestion of a full blood-meal occupied 24–72 hours in A. gambiae and 24–96 hours in A. funestus. The average dry season clutch of A. gambiae was 175 eggs and of A. funestus 123; wet season clutches appeared to be smaller.

scholarly journals Attribution of dry and wet climatic changes over Central Asia

2021 ◽  
pp. 1-57
Keyword(s):  
Surface Water ◽  
Vapor Pressure ◽  
Central Asia ◽  
Land Surface ◽  
Water Budget ◽  
Water Resource Management ◽  
Vapor Pressure Deficit ◽  
Moisture Flux ◽  
Dry Season ◽  
Wet Season

Abstract Central Asia (CA: 35°-55°N, 55°-90°E) has been experiencing a significant warming trend during the past five decades, which has been accompanied by intensified local hydrological changes. Accurate identification of variations in hydroclimatic conditions and understanding the driving mechanisms are of great importance for water resource management. Here, we attempted to quantify dry/wet variations by using precipitation minus evapotranspiration (P–E) and attributed the variations based on the atmosphere and surface water balances. Our results indicated that the dry season became drier while the wet season became wetter in CA for 1982–2019. The land surface water budget revealed precipitation (96.84%) and vapor pressure deficit (2.26%) as the primary contributing factors for the wet season. For the dry season, precipitation (95.43%), net radiation (3.51%), and vapor pressure deficit (−2.64%) were dominant factors. From the perspective of the atmospheric water budget, net inflow moisture flux was enhanced by a rate of 72.85 kg m−1 s−1 in the wet season, which was mainly transported from midwestern Eurasia. The increase in precipitation induced by the external cycle was 11.93 mm/6month. In contrast, the drying trend during the dry season was measured by a decrease in the net inflow moisture flux (74.41 kg m−1 s−1) and reduced external moisture from midwestern Eurasia. An increase in precipitation during the dry season can be attributed to an enhancement in local evapotranspiration, accompanied by a 4.69% increase in the recycling ratio. The compounding enhancements between wet and dry seasons ultimately contribute to an increasing frequency of both droughts and floods.

scholarly journals Improving early warning of drought-driven food insecurity in southern Africa using operational hydrological monitoring and forecasting products

2020 ◽  
Vol 20 (4) ◽  
pp. 1187-1201 ◽  
Author(s):  
Shraddhanand Shukla ◽  
Kristi R. Arsenault ◽  
Abheera Hazra ◽  
Christa Peters-Lidard ◽  
Randal D. Koster ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Food Insecurity ◽  
Crop Yield ◽  
Southern Africa ◽  
Early Warning ◽  
Root Zone ◽  
Severe Drought ◽  
Drought Event ◽  
Antecedent Soil Moisture ◽  
Monitoring And Forecasting

Abstract. The region of southern Africa (SA) has a fragile food economy and is vulnerable to frequent droughts. Interventions to mitigate food insecurity impacts require early warning of droughts – preferably as early as possible before the harvest season (typically starting in April) and lean season (typically starting in November). Hydrologic monitoring and forecasting systems provide a unique opportunity to support early warning efforts, since they can provide regular updates on available root-zone soil moisture (RZSM), a critical variable for crop yield, and provide forecasts of RZSM by combining the estimates of antecedent soil moisture conditions with climate forecasts. For SA, this study documents the predictive capabilities of RZSM products from the recently developed NASA Hydrological Forecasting and Analysis System (NHyFAS). Results show that the NHyFAS products would have identified the regional severe drought event – which peaked during December–February of 2015–2016 – at least as early as 1 November 2015. Next, it is shown that during 1982–2016, February RZSM (Feb-RZSM) forecasts (monitoring product) available in early November (early March) have a correlation of 0.49 (0.79) with the detrended regional crop yield. It is also found that when the February RZSM forecast (monitoring product) available in early November (early March) is indicated to be in the lowest tercile, the detrended regional crop yield is below normal about two-thirds of the time (always), at least over the sample years considered. Additionally, it is shown that the February RZSM forecast (monitoring product) can provide “out-of-sample” crop yield forecasts with comparable (substantially better with 40 % reduction in mean error) skill to December–February ENSO. These results indicate that the NHyFAS products can effectively support food insecurity early warning in the SA region. Finally, since a framework similar to NHyFAS can be used to provide RZSM monitoring and forecasting products over other regions of the globe, this case study also demonstrates potential for supporting food insecurity early warning globally.

scholarly journals Governance of Groundwater Resources in Transboundary Aquifers (GGRETA) - Phase 1 – 2013-2015- Main Achievements and Key Findings.

2017 ◽  
Author(s):  
Marina Rubio
Keyword(s):  
Central Asia ◽  
Case Studies ◽  
Central America ◽  
Southern Africa ◽  
Groundwater Resources ◽  
Phase 1 ◽  
Transboundary Aquifers ◽  
Assessment Activities

This brochure présents the main achievements and main results of phase 1 (2013-2015) of the GGRETA project, in particular by presenting a summary of the assessment activities of the 3 case studies (Stampriet Aquifer in Southern Africa, Trifinio Aquifer in Central America and Pretashkent Aquifer in Central Asia). Groundwater

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