L1 Flashcards
Define climate
climate is the average weather (mean and variability) over a specified time
define climate change
the change in climate with time due to natural variability or human activity
(IPPC)
define climate in earth system
land surface change, atmospheric composition, cryosphere (ice/snow)
what are some examples of observed climate variables?
Temperature (global mean surface, regional, diurnal range, upper air, ocean…)
Precipitation, humidity, cloud cover
Snow cover
Sea-ice thickness and extent
Natural modes (El Niño Southern Oscillation, North Atlantic Oscillation)
Climate extremes
Define anomalies
changes relative to some particular reference period
what are anomalies used to do?
identify positive and negative excursions from the start to end of a long term mean
wash jan- aug the warmest year on record
no it was the 2nd
how high is the current temperature of the water over the mean (2017)
0.69 degrees c
how high is the current temperature of the land over the mean (2017)
1.39 degrees C
Is warming stronger in the northern or southern hemisphere and why?
Northern
two reasons
- ocean currents
- more land in north which warms faster than the ocean
how do we measure upper air temperatures?
weather balloons (radiosondes) satellites (microwave sounding unit and stratospheric sounding unit)
how have upper air temperatures changed relative to the 1981 -2010 mean
- lower troposphere has warmed globally
- lower stratosphere has cooled
how would a volcanic eruption affect the temperature in the troposphere and stratosphere
cool troposphere
warm the stratosphere
what has been effected by changes in the cryosphere
snow cover
sea-ice extent
mountain glaciers
how have temperatures in the Arctic changed in the past 100 years
temperatures have increased almost 2x the global average
how have mountain glacier tongue length changed
169 glaciers measured, glaciers retreated worldwide, with 0 at 1950 (IPPC AR5, 2013)
what is the NAO and define it
North Atlantic Oscillation is a measure of circulation patterns in the northern hemisphere
what does a positive index of NAO mean for temperatures in Europe
positive temperatures in Europe
how has the temperature of days and nights changed in the last 50 years
more extremely warm days and nights but fewer cold days and nights
what extreme weather even occured in 2003
extreme heat wave
why are trends in precipitation complicated
due to precipitation being both rainfall and snowfall it makes it complicated to model
Over what period do we have “instrumental” measurements of temperature?
Since about 1880 using surface-based thermometers, but the record is far from truly global. Since the 1980s we have also had satellite radiometer measurements, which are more global
Has the rise in global mean temperature been fairly steady over the period for which we have direct measurements?
No, there was a clear period of fairly constant temperatures from the 1940s to the 1980s.
Over the last 40 years, the temperature has risen everywhere on the planet. True or false?
True. Almost everywhere. There are a few regions of very small changes or decreases.
How has the stratosphere responded to global warming?
It has cooled. This is consistent with a greenhouse gas effect, which traps heat in the lower atmosphere.
What explains the big spikes in temperature change in the stratosphere in 1982 and 1991?
Volcanic eruptions emitted lots of sulphate aerosol particles into the stratosphere, which persisted for over a year and caused stratospheric warming of up to 1 °C.
How does the change in temperature in the Arctic compare to the rest of the planet?
Double the temperature rise in the arctic in comparison to other areas.
Roughly how quickly has Arctic sea ice been receding since 1980, as measured by its extent at the end of the summer? About 1% per decade, about 5% per decade, or more than 10% per decade?
Over 10% per decade
Is the observed global pattern of changes in precipitation (rain and snowfall) consistent with the change in temperature?
Not really. The geographic pattern is actually quite mixed, with increases and decreases.
Since 1880, global mean sea level has risen by: About 1 cm, About 20 cm, or about 90 cm?
About 20 cm
