climate change indicators: upper atmosphere. global temperatures ghg emissions heat waves ...
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CLIMATE CHANGE INDICATORS:UPPER ATMOSPHERE
Global Temperatures GHG emissions Heat waves Drought Precipitation Flooding Cyclones Sea Surface Temp Sea level Ocean acidification
Arctic sea ice Glaciers Lake ice Snow cover Snowpack Growing season Plant hardiness Leaf/Bloom dates Bird wintering ranges
Changes occurring in the Lower Atmosphere (Troposphere)
It’s easy to notice or hear about change when it’s happening around you (in the troposphere)
What about the other layers of the atmosphere? Are changes occurring there?
How is the upper atmosphere measured from the ground?
RADAR (RAdio Detection And Ranging) is a technique for detecting and studying remote targets by transmitting a radio wave in the direction of the target and observing the reflection of the wave
Target of incoherent scatter radar is electrons in the earth's ionosphere rather than a discrete hard target (like an airplane)
High energy ultraviolet radiation from the sun removes electrons from some of the atoms and molecules in this region, and these electrons can scatter radio waves
Amount of energy scattered from each electron is well known, the strength of the echo received from the ionosphere measures the number of electrons in the scattering volume
Scattering technique can determine density, temperature, velocity, and composition of the charged upper atmosphere [ionosphere]
Incoherent Scatter Radar
• This map shows all of the world's operational incoherent scatter radars
• There are only 9 worldwide (as of 2000)
Where are Incoherent Scatter Radars?
MIT Haystack2000
Millstone Hill
Located in Westford, MA
Capable of making observations ranging from 90 to 1000 km in altitude
Radar system A fixed vertically pointing
antenna (Zenith) uses megawatt transmitter and 68 m diameter fixed antenna [1963 - now]
A fully steerable antenna (MISA), 46 meter diameter [1978 – now]
SWFX 5MIT Haystack
EISCAT/ESR
European Incoherent Scatter Scientific Association
It operates three incoherent scatter radar systems Two in Northern
Scandinavia One in Svalbard
Wikipedia | Credit Tom Grydeland
Arecibo
Radio Telescope located in Puerto Rico
305 m in diameter (largest single-aperture telescope)
Makes frequent appearances in movies and TV shows
NOAA accessed via Wikipedia
Jicamarca Radio Observatory (JRO)
Studies the equatorial ionosphere in Lima, Peru
Main antenna is the largest of all the incoherent scatter radars in the world 300m x 300m square
array Wikipedia | Public Domain
NASA Upper Atmosphere Satellite Projects
• TIMED - Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics
• Developed to explore Earth’s atmosphere above 60 km
• Launched December 2001
The Mission The Instrument
• SABER - Sounding of the Atmosphere using Broadband Emission Radiometry
• Aboard TIMED
• Designed to measure energy budget of the mesosphere and lower thermosphere
• Collected data over 8 years
NASA
Cutting Edge Research …
~40 years (1968 – 2006) of ionospheric data taken from the Millstone Hill Incoherent Scatter Radar is used
MIT scientists have been studying, analyzing and interpreting the results
Here is what they have discovered …
What trend do you notice?
Zhang, Shun-Rong | MIT Haystack
MIT Scientists state a +1.9K/year
Zhang, Shun-Rong | MIT Haystack
What trend do you notice?
Zhang, Shun-Rong | MIT Haystack
MIT Scientists state a -1.2 K/year
Zhang, Shun-Rong | MIT Haystack
What trend do you notice?
Zhang, Shun-Rong | MIT Haystack
MIT Scientists state a -3.2 K/year
Zhang, Shun-Rong | MIT Haystack
Zhang, Shun-Rong | MIT Haystack
Altitude vs. Ion Temperature % change per decade
There is more error in the lower atmosphere because there are fewer measurements made
The temperature profile indicates a DECREASE in ion temperature in the upper atmosphere above 200km
Zhang, Shun-Rong | MIT Haystack
Let’s Compare
Things are heating up … Average global
temperature has increased at a rate of roughly 0.15 - 0.20°C per decade over the past 40 years
This seems small, but has triggered many changes (polar cap melting, etc.)
Things are cooling down …
Trend shows a 2 - 3˚C decrease per decade over the past 40 years
Change is much bigger (10X!) than in the lower atmosphere
Total change is readily observable in data record
LOWER ATMOSPHERE UPPER ATMOSPHERE
What is causing the Upper Atmosphere to cool?
The answer is Radiative Cooling
Process by which a body
loses heat by radiation
Greenhouse gases (particularly CO2) radiative effects become more pronounced and produce a cooling effect in the upper atmosphere
Lastovicka et al. “Global Change in the Upper Atmosphere.” Science v.314 no.5803 (24 November 2006) pg. 1253 – 1254.
Active and Ongoing Research The upper
atmosphere is an area that requires further studied
More data is needed to confirm the observed trends
Observed change in upper atmospheric temperature is large, which makes it easier to measure Photo taken by Shun – Rong Zhang | used with permission