Base Esperanza, Antarctic Peninsula: An Adiabatic high for March 24, 2015?

Perhaps those who do not know the difference between a weather related effect and their … err … hip pocket should refrain from crowing too loudly:

Of course it is trumpeted that this is due to global warming.  Well, let us do a bit of reality checking on this.

First of all where is Esperanza Base?

At the northernmost part of Anarctica:

esperanza base google earth 5


It is about as far north as you can get in Antarctica and not be in Argentina.esperanza base google earth 4 jpegBase Esperanza fig. 1


esperanza base google earth 3Base Esperanza fig. 2


esperanza base google earthBase Esperanza fig. 3

It is located on Hope Bay and is an Argentine Base.  According to the wiki-link: It was built in 1953 and the base houses 55 inhabitants in winter, including 10 families and 2 school teachers.

Now if you look at the weather data for the day in question:

Base Esperanza March 24, 2015 mod

 (Right click on image and open in new tab to see larger.)

 Chart taken from Weather Underground here:

Now, I am not a weatherman.  I am not a Meteorologist.  But neither am I a complete dummy, either.  This looks like a weather event to me.  In fact it looks to me like this is an example of a Foehn wind or something similar.  From the wiki entry:

A Föhn or Foehn is a type of dry, warm, down-slope wind that occurs in the lee (downwind side) of a mountain range.

It is a rain shadow wind that results from the subsequent adiabatic warming of air that has dropped most of its moisture on windward slopes (see orographic lift). As a consequence of the different adiabatic lapse rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes. Föhn winds can raise temperatures by as much as 32 °C (58 °F)[1] in just a matter of minutes.


 Base Esperanza March 24, 2015 weather data table sm

(Right click on image and open in new tab to see larger.)

Now, if you take a look, between midnight and 6:00 a.m., the temperature was around 35-38 deg F.  The wind was light at 3.5 MPH.  Now look at 9:00 a.m.  The wind is out of the west at 43.7 miles per hour, the temperature has risen from the last reading to 59 deg F.  But the thing is, look at the humidity reading.  It falls steadily: 79,76,66 to 52% at 9:00.

If you look at Base Esperanza fig. 3, it sure looks to me like there are mountains to the west of the base.  Overall it looks to me like a good possibility for adiabatic or Foehn wind.

Now, one other thing to consider:

Base Esperanza weather underground astronomical data

(Right click on image and open in new tab to see larger.)

The chart from Weather Underground shows that the time of sunrise is 9:57.  So the temperature has risen well before sunrise.

Base Esperanza March 24, 2015 weather hq 5Humidity graph

(Right click on image and open in new tab to see larger.)

Now this is a graph of the relative humidity, taken from here:

It looks to me like the relative humidity drops pretty fair then recovers.  As it recovers, note that the temp drops.

Base Esperanza March 24, 2015 weather hq 1

Temperature graph (note, it is in degrees C.)

(Right click on image and open in new tab to see larger.)

You can pretty well see that the temperature spike is pretty short lived.  It is nothing more than a short duration effect caused by wind being warmed by the terrain.  Where I live this phenomenon is not all that uncommon, except that we call it a Chinook wind.

Nullschool shows the wind pattern that could very well cause the adiabatic effect:,-86.95,1420

ScreenShot nullschool


4 thoughts on “Base Esperanza, Antarctic Peninsula: An Adiabatic high for March 24, 2015?

    • That would do it for sure!

      I remember a few years back I went to bed at around 10 p.m in the middle of January. The temperature was somewhere around 15 F. Woke up the next morning it was almost 50 F. By late afternoon the foot or so of snow we had was gone, gone, gone. Then it started raining. By the next morning, there were several small dams and one 80 year old bridge that the authorities weren’t sure were going to hold up. With ground frozen still, all the snow melt and the rain did nothing but run off. Was interesting for a few days.


  1. It looks like NSIDC agrees with your assessment:


    Record warmth in Antarctica

    Air temperatures reached record high levels at two Antarctic stations last week, setting a new mark for the warmest conditions ever measured anywhere on the continent. On March 23, at Argentina’s base Marambio, a temperature of 17.4° Celsius (63.3° Fahrenheit) was reached, surpassing a previous record set in 1961 at a nearby base, Esperanza. The old record was 17.1° Celsius (62.8° Fahrenheit). However, Esperanza quickly reclaimed the record a few hours later on March 24, reaching a temperature of 17.5° Celsius (63.5° Fahrenheit).

    The cause of these warm conditions is familiar to people living in mountainous regions: a foehn or chinook wind, in which air flows up and over a steep mountain ridge. On the windward side, moisture is wrung out of the air mass in the form of rain or snow. As the air descends on the leeward (downwind) side, it compresses and warms.


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