THE OWNER OF THIS BLOG WILL NOT ACCEPT LIABILITY FOR ANY PROBLEMS OR MISTAKES THAT MIGHT ARISE FROM CALCULATIONS OR MATERIAL POSTED TO THIS PAGE:
You can get my easy to use wet bulb calculator program at http://gigsclerk.com/jobs/programming-technology/heat-wave-calculations/ for a dollar or two.
SEE https://www.facebook.com/Heat-Wave-533359286835145/ FOR CALCULATIONS ON WET BULB TEMPERATURES FOR YOUR AREA.
WET BULB CALCULATOR AT: http://www.srh.noaa.gov/epz/?n=wxcalc_rh Note that for coastal areas the pressure is usually around 760 mm of mercury. Up to an altitude of about 2 km the pressure difference does not make a big difference to calculations of wet bulb temperatures. At 2 km the wet bulb temperature might be up to 0.5 deg C or so less. You will have to find the relative humidity and temperature somewhere - perhaps from a weather report. After that you just need to enter the RH (relative humidity), the temperature and the pressure (perhaps 760 mm) into the calculator entry places.
Below are some of the messages I have been sending out to various sites:
The human body cannot cool itself below the wet bulb temperature by means of sweating. The wet bulb temperature is therefore an important indicator of the probability of heatstroke. This blog attempts to provide good information regarding the wet bulb temperature.
1) Keep relative humidity down. This means that you must not have too many people in a room as breathing and sweating, etc, can raise relative humidity.
2) Cool the walls, etc, with water from outside, etc. Radiation from walls, etc, increases the heat you receive.
3) You can cool yourself by drinking cold drinks, with ice, cold water and so on.
If you give me the temperature and relative humidity at your location I will do a wet bulb temperature calculation if there are not too many requests - see https://www.facebook.com/Heat-Wave-533359286835145/
TABLE YOU CAN USE TO DRAW YOUR OWN CONCLUSIONS: https://en.wikipedia.org/wiki/Heat_wave
gives a table with danger areas (relative humidity and temperature combinations)..
Example: T=36 deg C and RH (relative humidity)= 78. The wet bulb temperature is about 32.6 deg C. You are deep in the danger zone as a wet bulb temperature over about 30 deg C is dangerous if sustained
WORLD ECONOMY TO GET WORSE AS LABOR IS COMPROMISED BY GLOBAL WARMING?:
https://en.wikipedia.org/wiki/Wet-bulb_temperature states that, " A study by NOAA from 2013 concluded that heat stress will reduce labor capacity considerably under current emissions scenarios" as the world gets hotter and more humid. The site says, " A sustained wet-bulb temperature exceeding 35 °C (95 °F) is likely to be fatal even to fit and healthy people.." and "The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only " So if the temperature is 37 degrees Celsius and the relative humidity is 86% we have a wet bulb temperature of about 35 degrees Celsius (my calculations). Already in Port Elizabeth in March we have an average relative humidity of 81%. What about Durban and other humid places?
Talking about the heat wave in Pakistan that killed hundreds of people the Internet article "Wet Bulb Temperatures 35 C by Robertscribbler" says that wet bulb climbed into a dangerous range of 30 to 33 degrees Celsius. The wet bulb temperature is the coldest one can get via evaporation of water. The human body has an average temperature of 37 degrees Centigrade and cools itself by means of evaporation If the wet bulb temperature is 35 degrees Celsius or above the body cannot use evaporation to cool sweat below 35 deg C. This means that effectively the body cannot cool itself down and the person will probably die after a while. There is nowhere on Earth where the wet bulb temperature is as high as 35 deg C, but the article says in the Pacific record global atmospheric and ocean heat is pushing maximum sea surface temperatures into the lower 30s (typically between 30 and 31 degrees Celsius). THIS IS DANGEROUSLY CLOSE TO 35 deg C. You can calculate wet bulb temperatures by using a calculator on the internet (they do not always agree precisely with each other, but you should get an answer correct within 0.5 deg C or so). AN IDEA OF MINE: Pump seawater (or use the tide) into large shallow ponds and let it evaporate forming large salt crusts with high albedo that will reflect solar energy back into space. Do this on the perimeters of continents.https://en.wikipedia.org/wiki/Wet-bulb_temperature confirms that,
"The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only." What happens if the temperature is 37 deg C and the relative humidity is 85%. My program SWetbulb shows you could be in trouble.
You can download my program SWFridge that calculates the wet bulb temperature at groups.yahoo.com/neo/groups/wetbulb/info
LEAVING A DOG IN A CAR IN HOT CONDITIONS: Hyperthermia in dogs. The wet bulb temperature is the coldest one can get via evaporation of water. https://en.wikipedia.org/wiki/Wet-bulb_temperature confirms that, "The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only. A dog cools itself by panting and therefore evaporation. IF YOU LEAVE A DOG IN A CAR: Evaporation occurs as the dog pants to cool itself, so the relative humidity goes up, so the wet bulb temperature goes up, so the dog could become overheated and possibly die. The reason is that evaporation cannot cool the dogs mouth, etc, below the wet bulb temperature and the wet bulb temperature increases as the relative humidity increases.
COULD NEWSPAPERS , etc, INCLUDE WET BULB TEMPERATURES IN WEATHER REPORTS?
Wet bulb temperatures again (sorry, but it seems things are getting risky re heat waves). On 6 June 2015 THE NEW YORK TIMES reported the following:
(Beginning of report notes)
1) The wet-bulb temperature is not typically reported. While dangerous levels depend on a person’s activity level and clothing, wet-bulb temperature offers a stark measure of risk in a warming world that will experience more extreme combinations of both heat and humidity.
2) Statistical analyses and climate modeling indicate that the 2010 Russian heat wave was about five times more likely to have occurred in 2010 than it would have been in the cooler 1960s.
3) But sweating, which helps keep the core body temperature constant, becomes increasingly ineffective in increasingly humid air, and it can never cool the skin to below the wet-bulb temperature (end of report notes).
Personally, I think it is time to take serious note of wet bulb temperatures. Hopefully newspapers will start publishing them.
See http://www.nytimes.com/…/the-deadly-combination-of-heat-and…
