El Niño weakens
THE El Niño weather phenomenon has begun weakening after causing a severe drought, leaving over three million people in need of food aid.
With the weakening of El Niño, weather experts expect the occurrence of La Niña — an opposite phase of the El Niño Southern Oscillation cycle.
As predicted by the Meteorological Services Department (MSD) last year, the El Niño weather effect continued to ravage the country but has begun weakening as March 2016 comes to an end.
The unusually strong El Niño, coupled with record high temperatures, had a catastrophic effect on crops and rainfall across Zimbabwe with the hardest hit areas being the southern parts of the country.
Celebrating the World Meteorological Day last week, MSD head of public weather services, Tich Zinyemba, said 2015/2016 was a challenging season for the country.
“March is turning out to be like February, with March being a very wet month in terms of rainfall. The rains brought relief to many farmers as the rains provided drinking water and revived the pastures,” Zinyemba said.
The World Meteorological Organisation statement on the Status of the Climate in 2015 indicated that 2015 made history, with shattered temperature records, intense heat-waves and devastating droughts, which spilled into 2016.
“Based on an analysis of previous El Niño events, erratic rains, possibly leading to a late start, along with poorly distributed rains for the first half of the season, were experienced in all agro-ecological regions in Zimbabwe,” said Zinyemba.
El Niño turned the normal agricultural season in Zimbabwe upside down as some farmers planted late and others failed to plant anything as most of the rainfall failed to come during the first half of the rainfall season from October to December 2015.
The whole of southern Africa has experienced one of the worst droughts in the history of the region. Zimbabwe, once the region’s bread basket, is one of the worst affected countries, as it declared a state of disaster, appealing for US$1,5 billion, while neighbouring countries such as South Africa are also scrambling to import grain to feed its people and Lesotho also declared a state of emergency.
Estimates show that the prevalence of food insecurity in the rural population will fluctuate from 30 percent in April and 49 percent during the peak of the lean season from January to March 2017.
The World Meteorological Day commemorates the commencement of the Convention establishing the World Meteorological Organisation on March 23 1950. It showcases the essential contribution of National Meteorological and Hydrological Services to the safety and wellbeing of society.
The 2016 theme, Hotter, Drier, Wetter — Face the Future, highlights the challenges of climate change and the path towards climate-resilient societies.
The increase in hot days, warm nights and heat-waves will affect public health. These risks can be reduced by early warning systems that provide timely alerts to decision-makers, health services and the general public.
What are El Niño and La Niña?
El Niño and La Niña are complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific.
El Niño and La Niña are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle. The ENSO cycle is a scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific (approximately between the International Date Line and 120 degrees West).
La Niña is sometimes referred to as the cold phase of ENSO and El Niño as the warm phase of ENSO.
These deviations from normal surface temperatures can have large-scale impacts not only on ocean processes, but also on global weather and climate.
El Niño and La Niña episodes typically last nine to 12 months, but some prolonged events may last for years. While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years. Typically, El Niño occurs more frequently than La Niña.
El Niño
El Niño means The Little Boy, or Christ Child in Spanish. El Niño was originally recognised by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean. The name was chosen based on the time of year (around December) during which these warm waters events tended to occur.
The term El Niño refers to the large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific.
Typical El Niño effects are likely to develop over North America during the upcoming winter season. Those include warmer-than-average temperatures over western and central Canada, and over the western and northern United States. Wetter-than-average conditions are likely over portions of the U.S. Gulf Coast and Florida, while drier-than-average conditions can be expected in the Ohio Valley and the Pacific Northwest. The presence of El Niño can significantly influence weather patterns, ocean conditions, and marine fisheries across large portions of the globe for an extended period of time.
La Niña
La Niña means The Little Girl in Spanish. La Niña is also sometimes called El Viejo, anti-El Niño, or simply “a cold event.”
La Niña episodes represent periods of below-average sea surface temperatures across the east-central Equatorial Pacific. Global climate La Niña impacts tend to be opposite those of El Niño impacts. In the tropics, ocean temperature variations in La Niña also tend to be opposite those of El Niño.
During a La Niña year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.
Additional information from: http://oceanservice.noaa.gov/facts/ninonina