Record Warm February Nights Contribute to Record-Tying First Third Night-Time Heat Across Antigua

27 05 2016

Dale C. S. Destin |

Although the mean air temperature for the first third of the year – January to April, was near normal, night-time temperatures, as expressed by the mean minimum temperature, were at record-tying levels across much of Antigua.

For the first third, at the V. C. Bird International Airport (VCBIA), the mean minimum temperature of 23.5 °C (74.3 °F) equalled the record highest, tying that of 2010 and 1969. The long-term average minimum for January to April is 22.7 °C (72.9 °F).

At the same location, the mean minimum temperature for February was 23.4 °C (74.1 °F). This shattered the previous record of 22.2 °C (72.0 °F) for the month. The mean minimum for the other months, in the period, ranked in the top ten of the record dating back to 1969.

As has been observed globally, colder places, and in our case, colder times are warming faster than warmer times. On average, the first third of the year has the lowest mean minimum temperature; yet, it is warming at a faster rate than the other warmer two thirds (May-August, September-December) of the year – it is warming at a statistically significant rate of around 1.3 °C (2.34 °F) per hundred years.

MeanMinTemp

The blue straight line is the long-term temperature trend line

Regarding rainfall, for the first time in three years, we got our traditional April showers. The 1981-2010 long-term-average is 85.6 mm (3.37 in), and we got 79.0 mm (3.11 in), just 8% less than the average. Seatons Village and nearby areas were, however, quite wet with rainfall totals in excess of 150 mm (6 in). On the drier end of the spectrum were Five Islands and nearby areas with 34.3 mm (1.35 in).

Notwithstanding April’s rainfall, during the first third of the year the island-average rainfall for Antigua was below normal. However, it’s the highest in three years. Year-to-date, we have recorded 200.9 mm (7.91 in) of rainfall. This is 60.7 mm (2.39 in) below the long-term-average.

FirstThirdRainfall

The light blue straight line is the long-term rainfall trend line

Overall, annual rainfall is on an insignificant downward trend. Meanwhile, there is virtually zero change taking place with the rainfall for the first third of the year. However, April is getting wetter at a statistically significant rate of around 45.0 mm (1.77 in) per hundred years.

See our temperature and precipitation statements for more.

Follow us and be among the first to know the latest on our weather and climate.





The Status of Cold Temperature Extremes for Antigua

10 02 2016

Dale C. S. Destin |

Last week we had an extremely cold night (relative to our climate) and a few cool nights which led some persons to ask with “tongue-in-cheek” if we going to have snow. Are cold extremes becoming more or less frequent? What can we expect as our climate changes?

When I was growing up, I remember it was very common place to see our breaths (as mist) in the mornings, due to extremely low temperatures, at this time of the year. It was fun for us as we would pretend to be blowing smoke from our mouths and also blow mist onto the mirrors and then draw or write on them.

The fact is, such low temperature extremes, are decreasing fairly rapidly. So, the cold nights we had last week, are becoming more a thing of the past or a once in a “blue moon” event. 2015 had a record low number of extremely cold nights – 6 or 2% of the number of nights for the year; the next fewest is 2002 with 14 or 4%.

ExtremelyColdNights

Data at the V. C. Bird International Airport (VCBIA), where the Met Office is located, show a significant decline in extremely cold nights, while extremely warn nights are on the increase but not yet considered to be rising significantly.

ExtremelyWarmNights

Extremely cold nights here mean nights with the minimum temperature in the bottom 10-percentile based on the climate period 1971-2000. Extremely warm nights are those with minimum temperature in the top 10-percentile.

This year in particular, nighttime lows are expected to be much higher than normal due mainly to the ongoing El Nino or warmer than usual sea surface temperatures (SSTs) across the equatorial Pacific.

El Nino causes higher than normal surface pressure across the equatorial Atlantic, which acts to weaken the trade winds. Weakened trade winds then translate into warmer than normal SSTs and the air in contact with it; hence the warmer than normal nights.

As our climate changes, cold extremes will continue to decrease and warm extremes are expected to increase. Thus, the drop in temperature to cold extremes will become fewer and the spikes to warm extremes will become more and more common place

Weather extremes are generally undesirable. Cold extremes cost us nothing as it is fairly easy to warm ourselves. On the other hand, warm extremes have negative implications for our health, economy and ecosystem.

So far for the year, there have been fewer than normal extremely cold nights at the VCBIA – one, and more than normal warm nights – nine or 23% of nights to date for 2016.

Feel free to follow us for all things weather and climate at twitterfacebookinstagramtumblrflickrgoogle+, and youtube.





Widespread Coral Reef Bleaching for Antigua and Barbuda

13 10 2015

Dale C. S. Destin |

The highest coral bleaching alert level is forecast for Antigua and Barbuda and much of the Caribbean as a part of the third ever global coral bleaching event. Alert level 2 has been issued for our coral reefs.  This means that our coral reefs are expected to undergo widespread bleaching with a significant amount possibly dying.

Credit: NOAA Coral Reef Watch

Credit: NOAA Coral Reef Watch

The bleaching in our neck of the woods is due mainly to the warming of the Atlantic Ocean which was brought on by persistent light winds or negative North Atlantic Oscillation. Meanwhile, the Pacific bleaching is largely due to El Nino. Global warming is most likely playing an underlying role.

Corals start to bleach when the sea surface temperature (SST) exceeds the maximum monthly mean SST by 1 °C (1.8 °F). This cause corals to spew their algae, which they need to feed themselves. For our area, the bleaching threshold is 30.0 °C (86 °F). Currently, SST around Antigua is about 30.0 °C (86 °F) and rising.

Credit: NOAA Coral Reef Watch

Credit: NOAA Coral Reef Watch – http://coralreefwatch.noaa.gov

In the future, climate change, force by global warming, is expected to play a lead role in coral bleaching. According to the Inter-governmental Panel on Climate Change, warming in the top 100 metres of the ocean will rise a further 0.6 to 2 °C by the end of the 21st century. Greater warming is anticipated at the surface of the ocean. This could result in mass bleaching events becoming common place.

These images, taken in American Samoa, show the devastation caused by coral bleaching between December 2014 and February 2015 (Credit: XL Catlin Seaview Survey)

These images, taken in American Samoa, show the devastation caused by coral bleaching between December 2014 and February 2015 (Credit: XL Catlin Seaview Survey)

The bleaching has negative implications for our tourism industry. Coral reefs are a major source of sand for tropical beaches such as our 365 white sandy beaches, which are our main tourism drawing card. Degraded coral reefs could result in a decline in the replenishment of sand on our beaches and eventually reduce our islands’ attractiveness to tourists.

Additionally, many persons come to our shores to snorkel and enjoy the spectacular underwater beauty provided by coral reefs and the sea life they attract. Every coral bleached or killed reduces our drawing power of those tourists interested in this kind of scenery.

The bleaching also has negative implications for our food security, livelihoods, coastal protection, ocean acidification and climate change.

According to Professor Ove Hoegh-Guldberg of the University of Queensland, who was quoted in a recent BBC news article, “just like in 1998 and 2010, we’re observing bleaching on a global scale, which will cause massive loss of corals. With people relying on fisheries and reefs for sustenance, the repercussions could be potentially disastrous.”

Coral reefs are vitally important to Antigua and Barbuda and the rest of the world. They perform a long list of functions for us all. Chief among them is the role they play in the food chain. Corals serve as sanctuary for countless different species of fish. These reefs serve as homes for fish, without which they would be homeless with no place to safely have their babies.

The role played by coral reefs contributes in no small way to reef fish and mollusc, feeding as many as 40 million people annually.

Another important role coral reefs play is that of protecting our coastlines. For regions like ours that are visited by tropical cyclones (the generic term for tropical depressions, tropical storms and hurricanes) on an annual basis, coral reefs serve as a natural and vital protection against storm surge, strong currents and large waves by slowing down the water before it reaches the coastlines.

Coral reefs also play a very important role in the carbon cycle. They convert carbon dioxide (CO2) into limestone shell. Their absence would result in a rapid increase in CO2, which would eventually affect all living things on earth.

Generally, bleached corals end up dying. If they survive, their recovery can be very slow, taking decades.

The truth is, there isn’t a lot that we can do to mitigate a given bleaching event. However, systems could be put in place to keep our corals as healthy as possible by reducing pollution, coastal runoff and over fishing. Such measures would raise and keep corals at optimal health, which would improve their chances of surviving bleaching.

In the final analysis, if we are to continue to enjoy the products and services of our coral reefs, the world would have to make better than ambitious cuts to their CO2 emissions, the main cause of global warming and climate change. So far, the proposed cuts to emissions are still very far from what is required to keep global surface temperature below the level that will perhaps prevent the extinction of corals and dangerous climate change.

We will continue to follow this issue over the upcoming months and keep you informed.





Record Sea Surface Temperature for Antigua During January

27 02 2015

Dale C. S. Destin |

Sea surface temperatures (SSTs) around Antigua and Barbuda were at record tying levels during January.  The SSTs rose to 27.1°C, tying the record highest for January reached in 2010 and 1970. Interestingly, this occurred while much of the tropical North Atlantic had near normal SSTs.

RecordHighSSTsForJan2015

What does this mean?

It is not clear what this mean at this time. However, recent reports have linked the movement of fish poleward to cooler waters to climate change. That means movement of fish away the tropics, such as our area.

According to NOAA Fisheries scientist John Hare, it is hypothesized “that they’re heading north because they’re trying to stay within their preferred temperature range as the ocean warms up around them.” Thus, record warm SSTs cannot be good for fisheries and by extension our diet and economy.

Warm SSTs could also have negative implications for coral reefs. One of the stressors that lead to coral bleaching is high SSTs. Increased ocean temperatures are deemed the main cause of coral bleaching. As explained by NOAA’s scientists, “The bleaching takes place when corals are stressed by changes in conditions such as temperature, light or nutrients. They expel the symbiotic algae living in their tissues, causing them to turn white or pale. Without the algae, the coral loses its major source of food and is more susceptible to disease.”

Of some comfort though, the outlook for the period February-May 2015, issued by NOAA Reef Watch, shows coral bleaching to be unlikely for our area. However, most of the rest of the tropics and Southern Hemisphere subtropics are under watches and warnings.

CoralReefOutlookFeb-May2015

The two previous years of record high SSTs to start the year were associated with near record high rainfall years. In 2010 and 1970, the average rainfall totals for Antigua were 65.29 and 65.11 inches respectively. Only five other years have had higher rainfall dating back to 1928. However, this obviously is much too small a sample size to even start to think about this having any implications or portents for the rest of the year with respect to rainfall.

Looking forward…

We now turn our attention to the month of February to see if there is a continuation of the warm SSTs. Also we look forward to see if the warmth spreads to the tropical North Atlantic (TNA). Warm SSTs across the TNA is a good omen for rainfall across our area and vice versa.

 





Celebrating the International Year of Water Cooperation

24 01 2013

Without water there is no life. Humans, wildlife and agriculture cannot exist without it. The quality, quantity and distribution of water determine the world we live in: our health, physical safety, food security, cities, industries, power supplies and much more.

Millions of people lack access to safe drinking water and sanitation at a time when the demand for water, driven by growing populations and economies, continues to rise. Aging infrastructure and other inefficiencies lead to precious water being lost or wasted. Adding to these stresses, climate change is already affecting hydrological cycle and the pattern and intensity of floods and droughts. According to a recent United Nations survey, most countries report that water related risks and the competition for water resources have increased over the past 20 years.

Recognizing these challenges, the United Nations General Assembly declared 2013 the International Year of Water Cooperation. The purpose is to raise awareness of the many opportunities for governments to collaborate on promoting sustainable water management. The United Nations also established UN-Water as a platform for strengthening corporation within the United Nations system on all aspects of freshwater and sanitation.

Such global partnerships are encouraged by the Millennium Developmental Goals, which also include the goal of halving the number of people without access to safe drinking water and sanitation by the year 2015. Partnerships are also essential for addressing climate change and reducing potential conflicts over shared water basins and resources.

The World Meteorological Organization (WMO) promotes international cooperation on water through its Members [such as Antigua and Barbuda], which include the world’s National Meteorological and Hydrological Services (NMHSs). WMO contributions include measuring key variables such as rainfall and ground water levels, assessing water supplies, and providing hydrological forecasts for agricultural and urban planning. The WMO World Hydrological Cycle Observing System (WHYCOS) helps countries to establish an accurate, timely and accessible knowledge base for the sustainable development of their freshwater resources.

A further contribution is the Global Framework for Climate Services (GFCS), United Nations-wide initiative led by WMO that assists countries in addressing the risk and opportunities of climate variability and climate change. For example, climate services could help a country ensure that its water infrastructure, such as reservoirs and dams, remains well suited to changes in water supplies, extreme events and other variables shaped by climate. Or, by providing a better understanding of likely changes in the intensity and frequency of droughts or floods, climate services could guide investments in maintaining irrigation canals, building water storage towers, afforesting or reforesting hydrological basins, and so forth.

Together, these various forms of international cooperation offer the best path forward to a future where people everywhere can exercise their human right to safe drinking water and sanitation.

 

The above was taken from the WMO calendar for 2013








%d bloggers like this: