climate change indicators: upper atmosphere

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.

A quick video may help

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