April in N. Hemisphere Had 2nd-biggest 2-Month Temp Drop

Written by Roy W Spencer PhD on May 5, 2020. Posted in Current News

UPDATE: Changed emphasis from Northern Hemisphere extratropics to entire Northern Hemisphere (h/t John Christy)

In April 2020, the Northern Hemisphere experienced its second-largest two-month drop in temperature in the 497-month satellite record.

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for April 2020 was +0.38 deg. C, down from the March 2020 value of +0.48 deg. C.

The Northern Hemisphere temperature anomaly fell from +0.96 deg. C to 0.43 deg. C from February to April, a 0.53 deg. C drop that is the second-largest two-month drop in the 497-month satellite record. The largest two-month drop was -0.69 deg. C from December 1987 to February 1988.

The linear warming trend since January 1979 has now increased to +0.14 C/decade (but remains statistically unchanged at +0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).

Various regional LT departures from the 30-year (1981-2010) average for the last 16 months are:

 YEAR MO GLOBE NHEM. SHEM. TROPIC USA48 ARCTIC AUST 
 2019 01 +0.38 +0.35 +0.41 +0.36 +0.53 -0.15 +1.15
 2019 02 +0.37 +0.47 +0.28 +0.43 -0.02 +1.04 +0.06
 2019 03 +0.35 +0.44 +0.25 +0.41 -0.55 +0.97 +0.59
 2019 04 +0.44 +0.38 +0.51 +0.54 +0.49 +0.92 +0.91
 2019 05 +0.32 +0.29 +0.35 +0.40 -0.61 +0.98 +0.39
 2019 06 +0.47 +0.42 +0.52 +0.64 -0.64 +0.91 +0.35
 2019 07 +0.38 +0.33 +0.44 +0.45 +0.10 +0.33 +0.87
 2019 08 +0.39 +0.38 +0.39 +0.42 +0.17 +0.44 +0.24
 2019 09 +0.62 +0.64 +0.59 +0.60 +1.14 +0.75 +0.57
 2019 10 +0.46 +0.64 +0.28 +0.31 -0.03 +0.99 +0.50
 2019 11 +0.55 +0.56 +0.54 +0.55 +0.21 +0.56 +0.38
 2019 12 +0.56 +0.61 +0.50 +0.58 +0.92 +0.66 +0.94
 2020 01 +0.57 +0.60 +0.53 +0.62 +0.73 +0.12 +0.66
 2020 02 +0.76 +0.96 +0.55 +0.76 +0.38 +0.02 +0.30
 2020 03 +0.48 +0.61 +0.34 +0.63 +1.09 -0.72 +0.17
 2020 04 +0.38 +0.43 +0.34 +0.45 -0.59 +1.03 +0.97

The UAH LT global gridpoint anomaly image for April 2020 should be available within the next week here.

The global and regional monthly anomalies for the various atmospheric layers we monitor should be available in the next few days at the following locations:

Lower Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt

Mid-Troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tmt/uahncdc_mt_6.0.txt

Tropopause: http://vortex.nsstc.uah.edu/data/msu/v6.0/ttp/uahncdc_tp_6.0.txt

Lower Stratosphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tls/uahncdc_ls_6.0.txt

Read more at Dr. Roy’s Blog

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Comments (12)

Herb Ros

May 5, 2020 at 7:16 pm | #

For those who believe the atmosphere is heated by the surface of the Earth converting visible light into kinetic energy, this must come as a surprise. The output of visible light by the sun’s surface varies by less than 1% during the sunspot cycle. For anyone who believes that the oxygen and nitrogen in the atmosphere absorb the greater energy contained in the uv and x-ray wavelengths emitted by the sun and converts it into kinetic energy this is no surprise, since these wavelengths are emitted by solar flares which have disappeared in the grand solar minimum that has started. It’s going to get colder.

Reply
- tom0mason
  
  May 5, 2020 at 11:05 pm | #
  
  Interesting Herb,
  So as this paper https://arxiv.org/abs/1803.05436 says that during the last solar minimum (2008-2009) the high frequency end of the solar spectra rose.
  
  Between 2008-2009 (solar minimum) this component remains present, but the total emission is instead dominated by a new equatorial component with a brighter flux and harder spectrum. Most strikingly, although 6 gamma rays above 100 GeV are observed during the 1.4 years of solar minimum, none are observed during the next 7.8 years. These features, along with a 30-50 GeV spectral dip which will be discussed in a companion paper, were not anticipated by theory.
  
  Reply
  - Herb Rose
    
    May 5, 2020 at 11:30 pm | #
    
    Hi Tom,
    Yes it’s interesting that gamma radiation increased in a solar minimum. Gamma rays are produced when neutrons decay. I believe that neutron decay, radioactive atoms, and the energy produced by the sun are all the same process, fission. They are steps in the combining of energy with matter.
    I also believe that the model of the atom is wrong and the nuclear forces don’t exist. I don’t know if its worth $7 but I wrote a book “Reality Physics” available as an Amazon e-book that offers an alternate explanation of reality based on reason and evidence rather than the fantasy of current physics. You might find it interesting.
    Herb
    
    Reply
Andy Rowlands

May 5, 2020 at 8:29 pm | #

I don’t quite understand this, the February chart from UAH shows +0.76C not +0.96C.. I save each monthly chart so it was easy to look up. I also cannot see where the 0.43C number comes from.

Reply
- geran
  
  May 5, 2020 at 8:37 pm | #
  
  Andy, the “+0.96C” and “+0.43C” are for “Northern Hemisphere”. “+0.76C” is “Global”.
  
  Reply
geran

May 5, 2020 at 8:31 pm | #

Herb, how much solar energy do O2 and N2 absorb?

Reply
- Herb Rose
  
  May 5, 2020 at 9:21 pm | #
  
  Geran,
  It takes 450 kjoules/mole to split O2 into 2 O in order to create O3. It takes 950 kjoules/mole to split N2 into 2 N because of the triple bond. This is why above 100 km altitude the percentage of nitrogen decreases and the percentage of oxygen (as oxygen atoms) increases.
  
  Reply
  - geran
    
    May 5, 2020 at 9:27 pm | #
    
    Herb, I’ll try again. How much solar energy do O2 and N2 absorb?
    
    Reply
    - Herb Rose
      
      May 5, 2020 at 10:11 pm | #
      
      Geran, They absorb 95% of the uv coming from the sun and 100% of the x-rays which is why so little of the more energetic wavelengths reach the Earth’s surface. It is more solar energy than the energy contained in the visible wavelengths that penetrate the atmosphere. .
      
      Reply
      - geran
        
        May 5, 2020 at 10:32 pm | #
        
        UV at TOA is about 8% of total TSI. About half of that, or 4% TSI arrives Earth’s surface. So the amount absorbed by O2 and N2 is NOT “more solar energy than the energy contained in the visible wavelengths that penetrate the atmosphere.”
        
        Whatever source you’re using is clearly wrong.
tom0mason

May 5, 2020 at 10:53 pm | #

Nice work Roy W Spencer PhD 🙂 .

However Temperatures go up and temperatures go down.

If we stop and look at the BIG picture nothing very significant has happen over the last 100 years that has not happened over the 10,000 years and longer of natural temperature variations.
Our planet’s temperature has risen as it continues to leave the chill of the Little Ice Age. What caused that LIA cold spell – nobody truly knows! See https://climate4you.com/ and click on the link ‘The BIG picture ‘ to get some perspective as to where we are currently (especially Fig.3 AND Fig 4.)

What has happened is we’ve become quite good at measuring and recording the planet’s temperature, and at using many techniques with proxy data to tease-out the probable temperature record of the distant past and not much else. Why and how recent cold and warm events have happened are still mysterious and are subject to much conjecture. The sun’s variations appear to be a driver but how and why?

Reply
Graeme Mochrie

May 6, 2020 at 4:38 pm | #

I see that CO2 levels have continued to rise over lockdown months.

Reply