Week 7 - Past Climates Flashcards
Why are there differences between the Toronto downtown and airport temperature records?
Because of the urban heat island effect.
Why have the differences between Toronto Tmax and Tmin been getting smaller during the past century?
Because the urban heat island effect is really only visible at Min temps (overnight).
What other long term instrumental records exist in the world?
Uppsala, Stockholm, Central England
What are the issues with the Global Historical Climate Network?
The stations are mostly concentrated in America and Europe; also, the stations haven’t been around that long.
How accurate are instrumental records?
Not great. Problems include: thermometer calibration, standards of measurement, early rainfall and snow measurements probably underestimated.
What are the issues with automatic weather stations?
Accuracy and compatibility with older records.
What does the Kobe collection of data contribute to the historical temperature record?
Pressure, SST, winds.
What is Kobe?
Kobe Marine Observatory, Japan Meteorological Agency
Where does Kobe get its information?
Collected and archived weather data from ships, 1890-1960
What does the Global Reanalysis Project seek to do?
It seeks to fill the holes from 20th century data, help smooth over inconsistencies across sources, and employ new technology (satellites).
What contributions do satellite measurements make to the climate record?
Temperature, precipitation, sea ice and snow cover, and wave height and ocean altitude.
What is the measure of altitude called?
Altimetry
What does the instrumental record of temperature tell us about temperature during the period 1850-present?
That the temperature is steadily rising.
What is the relationship between 16O and 18O in ice cores and ocean sediments during glacial times?
During glacial times, 16O will evaporate and become trapped in ice sheets. That means more 18O in the ocean, which means more 18O in the foraminifera, which means more 18O in ocean sediment and more 16O in ice cores.
What is the relationship between 16O and 18O in ice cores and ocean sediments during interglacial times?
During interglacial times, 16O evaporates and goes back to the ocean, which means you’ll find a balance between ice sheets and oceans.
What does the oxygen isotope record show us about climate?
There have been at least 20 major glacial-interglacial cycles on Earth in past 2 MY.
How do boreholes show past temperatures of the atmosphere?
Once you’ve taken into account the energy from the Earth and other complicated math stuff, you can calculate the contribution from the sun, and therefore surface temps.
What is a proxy climate record?
Proxy = substitute. Climate for periods prior to the development of measuring instruments, including historic and geologic time.
What types of historical record can contribute to an understanding of climate change?
Diaries, ship logs, port accounts, merchant accounts, and newspapers.
What is pollen analysis, and how does it contribute to an
understanding of climate change?
By understanding what plants were around (as seen in lake sediment), we are able to determine the weather and climate at that time because types of plant species relates to weather.
What characteristics of tree rings can tell us something about paleoclimate?
They’re width, density, and isotopic composition.
How do dendroclimatologists extend the climate record back beyond the age of living trees?
By lining up living trees with deadwood and dendroarchaeological samples.
How much of the Earth is land and what should Earth probably be called?
Earth is 30% land and should probably be called Ocean.
What’s the foraminifera for a Friday night?
Neogloboquadrina pachyderma
How are deep sea cores obtained?
By drilling into the ocean floor with giant, CIA-funded boats.
Why is Neogloboquadrina pachyderma important in the
oceanic record of climate change?
Left-handed coils mean cooler overall temps; right-handed vice versa.
What is an isotope, and what oxygen isotopes are useful in understanding climate change?
An isotope is the same element with a different atomic mass. 16O and 18O.
What contribution can lake sediments make to the climate record?
Charcoal can show forest fires, therefore hot conditions. Coarse sediment can show runoff, so wet conditions. Also, pollen.
Why are there some differences between the historical
temperature records of the northern and southern
hemispheres?
Continentality.
Which place as the longest temperature series?
Central England
What can deep sea sediment tell us about?
The history of global temperature and ice ages.
What kind of terrain does the Kobe collection focus on?
Oceans
What are some examples of proxy climate records?
Tree rings, ice cores, pollen, sediments, boreholes, etc.
Which area of the world has the best geographic coverage of historic weather data?
Europe
What two things can borehole records tell us about?
Temperature fluctuations in the atmosphere and heat flow from the Earth.
What are the strengths of the Central England temp series?
Longest records, plus they’re British, and therefore smarter
What are the weaknesses of the Central England temp series?
Large area, calibration, inaccuracies, roving stations
