GHY 1011 Exam 3

Terms in this set (57)

instrumental surface temperature record
...measures the fluctuations of temperatures over a span of time
data sources and limitations
...CRUTEM - UK Hadley Center
GHCN - Global Historical Climate Network (NCDC)
GISS - NASA Goddard Institute for Space Studies
Berkeley - California Berkeley
Limitations - Potential sources of error in hemispheric or global mean temperature records:
At sea, huge gaps in monitoring networks
Improved reliability of weather instruments through the period of record
Changes in location & exposure of instruments
Warming effect of urbanization
global land surface temp annual anomalies
...Surface temperature records indicate significant warming has occurred nearly everywhere on Earth since 1900.
Warming has been most pronounced since the late 1970s and at high latitudes in the Northern Hemisphere.
almost 1 degree C increase since 1980s
annual anomalies of maximum, minimum, and daily temperature range
...BOTH maximum and minimum temperature range has increase approx. 1 degree C from 1950 - 2000; DTR has decreased since 1950 (very minor, not even .5 degrees C
land vs. ocean temperature patterns
...global mean temperatures have increased, average temperature over global land and ocean surfaces for February 2016 was the highest for February in the 137-year period of record, at 1.21°C (2.18°F) above the 20th century average of 12.1°C (53.9°F)
latitudinal temperature patterns (tropics v. polar regions)
...polar = AO, when the jet stream is farther north that means less likely to have colder weather in the winter months is US and mid latitude regions (positive AO), when jet stream is farther south (negative AO), colder temperatures in winter months in mid latitudes; By disrupting the atmospheric circulation in the planet's largest ocean basin, El Niño (warm phase) shifts the average location and strength of the mid-latitude jet sreams, less rainfall in Indonesia (cooler), La Nina (cool phase) trade winds in tropics stronger than usual, tropical pacific cooler (less rainfall), Indonesia gets more rainfall (warmer)
urban heat island effects
...Some individual stations may be affected . . . but all global-scale studies indicate the urban heat island affect is a very small component of large-scale averages; more people, homes, industry, electricity, etc. actually effects the temperature as opposed to to rural areas... ASPHALT
urban vs. rural temperature anomalies
...industry = heat, less people and industry = less heat, can vary up to 5 degrees C
instrument siting concerns: good vs. bad
...Suggests that station siting quality (e.g., 1 vs. 5) is more important influence on temperature bias than geographical location.
cooperative observer stations (COOP)
...observation and data collected by volunteers = data usually consist of daily maximum and minimum temperatures, snowfall, and 24-hour precipitation totals
urban bias temperature?
...Some individual stations may be affected . . . but all global-scale studies indicate the urban heat island affect is a very small component of large-scale averages
linear trend of annual temperatures
...upward increase of annual temperatures;The trend in global mean temperature was generally upward from 1880 until about 1940, downward or steady from 1940 to about 1970, and upward again through the 1990s and early 2000s
changes in large-scale precipitation trends
...No statistically significant linear trends in global precipitation from 1900 to 2012, but considerable variability exists; Numerous challenges in measuring precipitation due to wind effects and accurate measurement of snowfall
spatial patterns of precipitation trends
...Wetter conditions across Amazon Basin and Patagonia in South America
Drier, then wetter across the African Sahel
Change in rainfall patterns may be tied to 1976-1977 Pacific Climate Shift
changes in snowfall
...Winter precipitation has increased at high latitudes.
Rising temperatures have generally resulted in rain rather than snow in locations and seasons where climatological average (1961-1990) temperatures were close to 0°C.
Large increases in lake-effect snowfall since 1951 for locations near the Great Lakes, consistent with observed decrease in ice cover since the early 1980s.
ocean precipitation
...cyclones, hurricanes, typhoons, etc, warmer oceans = more intense precipitation
drought changes and evapotranspiration
...A combination of factors that interact in a complex way lead to a
drought - Lack of precipitation, temperature, evaporation rates, soil moisture, etc., Human activity such as land and water usage; evapotranspiration - the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants
types of drought
...Drought: "prolonged absence or marked deficiency of precipitation"
Agricultural drought relates to moisture deficits in the root zone of the soil that impacts crops.
Meteorological drought is mainly a prolonged deficit of precipitation.
Hydrologic drought is related to below normal streamflow, lake, and groundwater levels.
PDSI (Palmer Drought Severity Index) is most commonly used drought index, using precipitation, temperature, and water content data to assess soil moisture.
data sources of analyzing troposphere temperature trends: radiosondes, satellites, global reanalysis data from numerical models
...Radiosondes - From 2x daily upper air soundings,Began in 1940s regionally, 1958 globally
Satellite Microwave Sounding Unit - Converts measures of microwave emissions to temperature, Data available since 1978
Global Reanalysis Data - From numerical models
troposphere
...The troposphere is the lowest layer of Earth's atmosphere and site of all weather on Earth. The troposphere is bonded on the top by a layer of air called the tropopause, which separates the troposphere from the stratosphere, and on bottom by the surface of the Earth.
stratosphere
...the layer of the earth's atmosphere above the troposphere, extending to about 32 miles (50 km) above the earth's surface (the lower boundary of the mesosphere).
skew-T plots
...an almost instantaneous snapshot of the atmosphere from the surface to about the 100 millibar level; weather balloons
tropopause
...The boundary between the troposphere and the stratosphere, where an abrupt change in lapse rate usually occurs. It is defined as the lowest level at which the lapse rate decreases to 2 °C/km or less, provided that the average lapse rate between this level and all higher levels within 2 km does not exceed 2 °C/km; temperature as a function of height varies continuously through the atmosphere but the temperature gradient does not
temperature inversion
...condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude. When temperature inversion occurs, cold air underlies warmer air at higher altitudes.
global and tropical trends in atmosphere
...width of tropical belt has increased since 1979;
pacific climate shift
...1977, major change in ocean temperatures, colder water was replace by warmer water, this huge shift results in more frequen tEl Nino type effects when PDO is warm (positive), when PDO is cooler, it results in more frequent La Nina type effects (negative)
pacific decadal oscillation
...El Niño-like pattern of Pacific climate variability, either warm or cool, depending on ocean temperature anomalies in the northeast and tropical Pacific Ocean, sea surface temps are cool in the interior North Pacific and warm along the Pacific Coast, and when sea level pressures are below average over the North Pacific, the PDO is more; warm SST anomalies in the interior and cool SST anomalies along the North American coast, or above average sea level pressures over the North Pacific, the PDO is less
arctic oscilliation
...winds circulating counterclockwise around the Arctic at around 55°N latitude, AO is in its positive phase, a ring of strong winds circulating around the North Pole acts to confine colder air across polar regions; AO is negative when winds are weakened/distorted and allows for southward movement of colder air = arctic air masses and storminess in mid-latitudes (snow storms possible)
north atlantic oscillation
...based on the surface sea-level pressure difference between the Subtropical (Azores) High and the Subpolar Low, below-normal heights and pressure across the high latitudes of the North Atlantic and above-normal heights and pressure over the central North Atlantic, the eastern US (mid-latitudes) = positive, above-normal heights in pressure across high latitudes and below-normal heights and pressure in N Atlantic and Mid latitudes =negative; associate with basin-wide changes in the intensity and location of the North Atlantic jet stream and storm track
ENSO
...a periodic fluctuation in sea surface temperature (El Niño) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean,
changes in atmospheric circulation since the 1970s
...Warm-phase of ENSO (El Niño) has accelerated tropical Andean glacier retreat since the late 1970s;
extreme events
... Heat waves, Prolonged cold, Drought, Flood, Storms; Extremes refer to rare events based on a statistical model of particular weather elements; Frequency of warm nights has increased and frequency of cold nights has decreased, Frequency of hot days in some parts of world has increased, Heavy precipitation events have increased in frequency, 2011 saw more extreme events in the U.S. than any other year in history
warm arctic cold continents patterns
...low autumn sea ice, rapid autumn snow cover advance, and a negative winter Arctic Oscillation, Regressions between autumnal sea ice extent and Eurasian snow cover extent and Northern Hemisphere temperatures
are tropical cyclones getting stronger?
...Theory and modeling predict that tropical cyclone intensity should increase with increasing global mean temperatures; Power Dissipation Index (PDI), a measure of potential destructivenss of tropical cyclones, has increased markedly since the mid-1970s, PDI is highly correlated with tropical sea-surface temperatures (SSTs); the jury is still out BUT a substantial human influence on future tropical cyclone activity cannot be ruled out, however, and could arise from several mechanisms (including oceanic warming, sea-level rise, and circulation changes).
tropical cyclone frequency and north carolina
...North Carolina coast experiences a higher frequency of tropical cyclone activity than anywhere else in the Atlantic basin; Changes in tropical cyclone activity will have a significant impact on North Carolina!
tropical cyclones and global warming: basic theory and modeling, observations
...Frequency, intensity, and rainfall
Genesis, tracks, duration, and surge flooding; Theory and modeling predict that tropical cyclone intensity should increase with increasing global mean temperatures
tropical cyclone trends: frequency, intensity (power dissipation index), destructiveness, attribution
...Power Dissipation Index (PDI), a measure of potential destructivenss of tropical cyclones, has increased markedly since the mid-1970s, PDI is highly correlated with tropical sea-surface temperatures (SSTs); 2011 was the year of extreme events, Theory and modeling predict that tropical cyclone intensity should increase with increasing global mean temperatures
Kerry Emanuel
...Massachusetts Institute of Technology (MIT), PDI correlates with rising sea-surface temps, has increased a lot since 1970s, "Results suggest that future warming may lead to an upward trend in tropical cyclone destructive potential and - taking into account an increasing coastal population - a substantial increase in hurricane-related losses in the twenty-first century", global mean temps rising = increased cyclone intensity
Roger Plelke, Jr.
...University of Colorado, "My analysis of a long-term data set of hurricane losses in the United States shows no upward trend once the data are normalized to remove the effects of societal changes."
". . . it is misleading to characterize Emanuel's results as indicating an increase in 'destructiveness' or as an indication of future increases in destruction resulting from changes in the PDI."
Christopher Landsea
...NOAA's National Hurricane Center, believes the record of tropical cyclones is too short to make assumptions, believes the connection between global climate change/warming and Atlantic hurricanes premature
Knutson et al. (2010)
..."We cannot at this time conclusively identify anthropogenic signals in past tropical cyclone data."
"A substantial human influence on future tropical cyclone activity cannot be ruled out, however, and could arise from several mechanisms (including oceanic warming, sea-level rise, and circulation changes)."
2011: year of extremes
...more extremes in US than any other in history
hurricane sandy
...more heat in the oceans = more energy = higher winds in hurricanes, more heat in oceans also = longer hurricane seasons, category 3 storm, strongest in season, made landfall in NJ
2015 northern hemisphere tropical cyclone season
...27 tropical cyclones in Atlantic basin, winds greater than 111mph, 58 ACE = N Atlantic, 10 named storms; 14 Cat. 3 storms in NW Pacific, 24 named storms total, Accumulated Cyclone Energy = 274 in NWP; N Indian = 26 ACE
cryosphere
... the frozen water part of the Earth system, includes: frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic.
seasonal snow cover
reduction of 5% in 1988-2004 annual average area compared to 1967-1987 annual average area
Greenland Ice Sheet
...Largest island on Earth (81% covered by ice)*, First group of settlers (from Iceland) in A.D. 985, Population of Greenland is ~56,000, Population of Boone, N.C. is ~17,189, Capital is Nuuk, A territory of Denmark, HUGE glacier, thickness of 3.3km (2mi), Total ice loss from both Greenland and Antarctica between 1992 and 2011 was equivalent to 11.7 mm of sea level; Future destabilization of ice sheets could cause sea level to rise substantially.
ice sheet dynamics and stability
...Emanating from the periphery of the ice sheet are many smaller ice streams and outlet glaciers that drain the main ice sheet and release icebergs into the ocean, Glaciers on ice sheet, drain the interior, returning this water to the sea as icebergs. Meltwater can accelerate the flow of a glacier by lubricating the underside as it scrapes over the rocky terrain
trends in glacier mass balance
...melting/retreat = Total ice loss from both Greenland and Antarctica between 1992 and 2011 was equivalent to 11.7 mm of sea level, Future destabilization of ice sheets could cause sea level to rise substantially
Cordillera Vilcanota, Peru
...glacier in Andes, glacial retreat a result from PDO since late 1970s and more frequent El Nino temperature patterns, ecological systems are impacted as well as water resources for natives
climate-glacier interactions in Andes
...glacial retreat = less fresh water resources for populations on leeward side of Andes, mining # 1 industry, glaciers retreat, access to more places for mining, exposing rocks that have been under impact from glacier = exposing sulfide rich, metal rich rocks which contaminate water supply making it deadly for natives
temperature gradient
... a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature gradient is a dimensional quantity expressed in units of degrees (on a particular temperature scale) per unit length.
snow, river and lake ice
...annual duration reduced by 12 days in the past 150 years
sea ice (thickness)
...mean annual arctic extent decreased by 2.7% per decade since 1978, summer minimum decrease by 7.4% per decade since 1978
glaciers and ice caps
...shrinking at an increased rate and contributing 0.8 mm per year to sea level rise for 1991-2004
frozen ground
...permafrost is warming and the active layer is thickening, seasonally frozen ground has decreased in maximum extent (by 7%) since 1900
ice sheets and ice shelves
...sheets - combined Greenland and Antarctica contribution to sea-level rise between 0.0 and 0.8 mm per year; shelves - Antarctic Peninsula and Amundsen Sea shelves thinned in 90's, Larsen B shelf collapsed in 92, with subsequent acceleration of tributary ice streams
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