Heat Dome | Roasted Death Valley | UPSC

Heat Dome | Roasted Death Valley

      HEADLINES:

Did Death Valley just hit the highest temperature recorded ever

      WHY IN NEWS:

The Death Valley had recorded a temperature of 129°F in July 2013.The temperature on August 16 has surpassed it.

SYLLABUS COVERED: GS 1 : 3 : Geography : Climate Change

      LEARNING: 

For PRELIMS go through the new definition – Heat Dome and OMT . Highest and lowest are rarely asked but yes skim through the areas on the globe . It is time to Map .

      ISSUE: 

BOILING TEMPERATURE

California’s Death Valley registered a temperature of 54.4 degrees Celsius or 129.9 degrees Fahrenheit on August 16, 2020.

•  Which once verified, could be the hottest temperature ever recorded on Earth.
• United States weather station at Furnace Creek recorded this in Nevada, at 3:41 pm local time .

PREVIOUS RECORDS

The all-time highest temperature ever recorded is 134°F or 56.7°C on July 10, 1913, at the Greenland Ranch in the Death Valley.

• However, since the temperature-recording mechanisms was not as advanced, many have doubted if that reading was reliable.
• Similarly, a reading of 131°F or 55°C from July 1931 in Tunisia, has also been challenged.
• The high temperature recorded on August 16 is a result of a so-called ‘heat dome’ .

WHAT IS A HEAT DOME?

A heat dome occurs when the atmosphere traps hot ocean air like a lid or cap.

• Summertime means hot weather — and extreme heat waves have become more frequent in recent decades.
• Sometimes, the scorching heat is ensnared in what is called a heat dome.

SOURCES : NOAA

CAUSES

This happens when strong, high-pressure atmospheric conditions combine with influences from La Niña.

• This creates vast areas of sweltering heat that gets trapped under the high-pressure “dome“.
• The main cause is a strong change (or gradient) in ocean temperatures from west to east in the tropical Pacific Ocean .

Western Pacific’s temperatures have risen over the past few decades as compared to the eastern Pacific, creating a strong temperature gradient.

• Alternatively, these pressure differences that drive wind, across the entire ocean in winter.

PRINCIPLE

• In a process known as convection, the gradient causes more warm air, heated by the ocean surface.
• This rises over the western Pacific, and decreases convection over the central and eastern Pacific.

As prevailing winds move the hot air east, the northern shifts of the jet stream trap the air.

• Thus winds move it toward land, where it sinks, resulting in heat waves.

OCEAN MEAN TEMPERATURE (OMT)

• These are important climatic parameters required for atmospheric and oceanic studies like cyclone and monsoon predictions .

The aim here is to calculate ocean heat transport estimations.

The data used to estimate these parameters are :

(a) sea surface height anomaly (SSHA) from the available altimeters

(b) sea surface temperature (SST).

      IASbhai WINDUP: 

• The temperature recorded at Furnace Creek has been termed as ‘preliminary’ and not ‘final’.
• Some have said that if it is verified as correct, it will be a new record.
• The heat dome is likely to continue into August 17 and August 18.
• This year has already seen various extremes in temperature.

A LITTLE WHILE BACK

• The wildfires of Australia in December 2019 memories are still fresh .
• The fires have been among the deadliest, with 20 per cent of Australia’s forests burnt.

• In June, Siberia began to burn because of wildfires caused by intense heat.

     SOURCES:THE HINDU & PIB | Heat Dome | Roasted Death Valley

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