The GCM's overestimation
of precipitation frequency interferes with its skill to simulate the warmest summers characterized by relatively low precipitation.
Not exact matches
It also has seen a 71 percent increase in the
frequency of extreme
precipitation events — more than any other region in the United States, according to the paper.
The intensity, duration, and
frequency of extreme temperature - and
precipitation - based events are key components to understanding the climate
of Chesapeake Bay.
«If we look at
precipitation events over the long term, there is an increase in
frequency of extremes.
The panel finds that humans have already contributed to an increase in the
frequency and duration
of heat waves and an intensification
of heavy
precipitation events.
CLOUDY WITH A CHANCE
OF ERUPTION Yellowstone's Old Faithful geyser is famous for its near - clocklike regularity, but scientists with the U.S. Geological Survey recently determined that annual precipitation influences the overall frequency of eruptions in Yellowstone: The more it rains and snows nearby, the more often the geysers po
OF ERUPTION Yellowstone's Old Faithful geyser is famous for its near - clocklike regularity, but scientists with the U.S. Geological Survey recently determined that annual
precipitation influences the overall
frequency of eruptions in Yellowstone: The more it rains and snows nearby, the more often the geysers po
of eruptions in Yellowstone: The more it rains and snows nearby, the more often the geysers pop.
The authors predict a 25 % rise in the
frequency of precipitation whiplash events by the end
of the twenty - first century in northern California, increasing up to 100 % in southern California.
Daniel Swain and colleagues model how the
frequency of these rapid, year - to - year transitions from extreme dry to wet conditions — which they dub «
precipitation whiplash events» — may change in California's future as a consequence
of man - made warming.
Researchers charge global warming with projected significant increases in the
frequency of both extreme
precipitation and landfalling atmospheric rivers
However, there has been a general trend
of decreasing winter
precipitation from 1950 to present; this pattern is most evident in the northwest and central portions
of the state and may be due to increased
frequency of El Niño events (see Climate chapter).
Spatial - temporal analysis
of United States
precipitation data from 1900 to 1999 indicates that the Atlantic Multidecadal Oscillation (AMO) primarily modulates drought
frequency.
This is addressed by evaluating change in global or large - scale patterns in the
frequency or intensity
of extremes (e.g., observed widespread intensification
of precipitation extremes attributed to human influence, increase in
frequency and intensity
of hot extremes) and by event attribution methods.
According to Ghosh, the fast growth rate
of these snails makes them «ideal candidate [s] to record high -
frequency changes in the monsoon
precipitation.»
The
frequency and amount
of precipitation falling in intense events are underestimated.
Using high - resolution modeling with theoretical and statistical analysis, researchers revealed a direct link between in - cloud processes and the
frequency of precipitation extremes.
With each increment
of warming, the
frequency of hot extremes and heavy
precipitation events worldwide rises dramatically.
Where antecedent A1 represents mean temperature, A2 represents mean
precipitation, A3 represents mean ground frost
frequency, A4 represents altitude, consequent B represents the number
of individual plant species occurrences and E2 represents the stress tolerant - ruderal plant strategy
of the plant species present.
Data
of climate variables (mean
precipitation; mean temperature; mean ground frost
frequency) at monthly intervals (1961 - 90) were sourced from the IPCC (http://www.ipcc-data.org).
Mean temperature was noted as A1 (n,..., n),
precipitation was noted as A2 (n,..., n), mean ground frost
frequency was given as A3 (n,..., n), altitude was noted as A4 (n,..., n), the number
of species was noted as B (n,..., n).
The assessment considered the impacts
of several key drivers
of climate change: sea level change; alterations in
precipitation patterns and subsequent delivery
of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in
frequency and intensity
of coastal storms; and increased levels
of atmospheric CO2.
This rhythm in storm
frequency may explain some
of the recently observed increases in extreme
precipitation events.
These variability trends indicate that the
frequency of extremes (more drought events and more heavy
precipitation events) has increased whereas the mean has remained approximately the same.
Mean temperature, mean monthly
precipitation,
frequency of hot / cold days / nights, and indices
of extreme
precipitation are all estimated for each country based on observed and modeled data.
I should add too that I was not allowed at work to study or talk about trends in
frequency and magnitude
of floods or trends in temperatures and
precipitation, due to the «highly political and controversial subject
of global warming».
I certainly agree that continued warming will increase the
frequency of a variety
of extremes related to heat, sea level,
precipitation, etc. and in fact, some
of that is already happening.
«Century
of Data Shows Intensification
of Water Cycle but No Increase in Storms or Floods Released: 3/15/2006 12:13:21 PM» (excerpt) A review
of the findings from more than 100 peer - reviewed studies shows that although many aspects
of the global water cycle have intensified, including
precipitation and evaporation, this trend has not consistently resulted in an increase in the
frequency or intensity
of tropical storms or floods over the past century.
A clear and more detailed explanation can be found in Section 2.1
of the Simmons et al 2010 JGR article «Low -
frequency variations in surface atmospheric humidity, temperature, and
precipitation: Inferences from reanalyses and monthly gridded observational data sets» (doi: 10.1029 / 2009JD012442).
-- Projected
precipitation and temperature changes imply changes in floods, although overall there is low confidence at the global scale regarding climate - driven changes in magnitude or
frequency of river - related flooding, due to limited evidence and because the causes
of regional changes are complex.
Second Assessment
of Climate Change for the Baltic Sea Basin https://books.google.com/books?isbn=3319160060 The BACC II Author Team averaged
frequency of extreme 1 - day
precipitation totals above 15 mm and a... 4.6 Cloudiness and Solar Radiation 4.6.1 Cloudiness Records
of cloudiness and solar... There is a trend
of decreasing cloud cover over the Baltic Sea basin......
-- It is likely that the
frequency of heavy
precipitation will increase in the 21st century over many regions.
-- Increases in intensity and
frequency of heat waves and extreme
precipitation events (a category in which it includes droughts, floods, hurricanes and major storms)
Without El Niño and La Niña feeding into the climate model, the
frequency of extreme
precipitation in California stayed constant for the simulation's century and a half.
Visible changes in hydrological cycle have been observed in the form
of changing
precipitation patterns, cropping patterns, droughts, water availability periods,
frequency and intensity
of heatwaves,
precipitation events and weather - induced natural disasters.
They include soaring temperatures, declining late - season snowpack, northward - shifted winter storm tracks, increasing
precipitation intensity, the worst drought since measurements began, steep declines in Colorado River reservoir storage, widespread vegetation mortality, and sharp increases in the
frequency of large wildfires.
Whether climate change is expressed as a rise in temperatures, or as changing
precipitation patterns — it is at the extreme edges
of the graph that the
frequency of weather events suddenly multiplies dramatically.
This is especially true for the temperature extremes, but intensity,
frequency and distribution
of extreme
precipitation are less well simulated.
This criterion may not be satisfied if observations are available only over a short time period (as is the case for the vertical structure
of clouds), or if the predictor is defined through low -
frequency variability (trends, decadal variability), or if there is a lack
of consistency among available datasets (as in the case for global - mean
precipitation and surface fluxes).
These might include the
frequency and intensity
of precipitation or heat waves, as well as other phenomena that occur naturally but whose magnitude or
frequency could be subject to anthropogenic influences.
Accordingly, there is less certainty about the changes in
frequency and intensity
of tropical cyclones on a regional basis than for temperature and
precipitation changes.
Increases in the
frequency and intensity
of extreme
precipitation events are projected for all U.S. regions.
Snowfall varies across the region, comprising less than 10 %
of total
precipitation in the south, to more than half in the north, with as much as two inches
of water available in the snowpack at the beginning
of spring melt in the northern reaches
of the river basins.81 When this amount
of snowmelt is combined with heavy rainfall, the resulting flooding can be widespread and catastrophic (see «Cedar Rapids: A Tale
of Vulnerability and Response»).82 Historical observations indicate declines in the
frequency of high magnitude snowfall years over much
of the Midwest, 83 but an increase in lake effect snowfall.61 These divergent trends and their inverse relationships with air temperatures make overall projections
of regional impacts
of the associated snowmelt extremely difficult.
Figure 9.6: Maps show the increase in
frequency of extreme daily
precipitation events (a daily amount that now occurs just once in 20 years) by the later part
of this century (2081 - 2100) compared to the latter part
of the last century (1981 - 2000).
Given projected increases in the
frequency and intensity
of extreme
precipitation events in the Midwest (Chapter 2: Our Changing Climate, Key Message 6), 57 it appears that sewer overflow will continue to constitute a significant current health threat and a critical source
of climate change vulnerability for major urban areas within the Midwest.
For the entire Northern Hemisphere, there is evidence
of an increase in both storm
frequency and intensity during the cold season since 1950,1 with storm tracks having shifted slightly towards the poles.2, 3 Extremely heavy snowstorms increased in number during the last century in northern and eastern parts
of the United States, but have been less frequent since 2000.11,15 Total seasonal snowfall has generally decreased in southern and some western areas, 16 increased in the northern Great Plains and Great Lakes region, 16,17 and not changed in other areas, such as the Sierra Nevada, although snow is melting earlier in the year and more
precipitation is falling as rain versus snow.18 Very snowy winters have generally been decreasing in
frequency in most regions over the last 10 to 20 years, although the Northeast has been seeing a normal number
of such winters.19 Heavier - than - normal snowfalls recently observed in the Midwest and Northeast U.S. in some years, with little snow in other years, are consistent with indications
of increased blocking (a large scale pressure pattern with little or no movement)
of the wintertime circulation
of the Northern Hemisphere.5 However, conclusions about trends in blocking have been found to depend on the method
of analysis, 6 so the assessment and attribution
of trends in blocking remains an active research area.
2: Our Changing Climate, Key Message 5).2 Regional climate models (RCMs) using the same emissions scenario also project increased spring
precipitation (9 % in 2041 - 2062 relative to 1979 - 2000) and decreased summer
precipitation (by an average
of about 8 % in 2041 - 2062 relative to 1979 - 2000) particularly in the southern portions
of the Midwest.12 Increases in the
frequency and intensity
of extreme
precipitation are projected across the entire region in both GCM and RCM simulations (Figure 18.6), and these increases are generally larger than the projected changes in average
precipitation.12, 2
Following a centuries - long dry period with high fire
frequency (c. AD 1400 - 1790), annual
precipitation increased, fire
frequency decreased, and the season
of fire shifted from predominantly midsummer to late spring....
The
frequency of heavy
precipitation events has already increased for the nation as a whole, and is projected to increase in all U.S. regions (Ch.
There are also multiple studies associating extreme
precipitation events with waterborne disease outbreaks.59 This evidence
of responsiveness
of waterborne disease to weather and climate, combined with evidence strongly suggesting that temperatures will increase and extreme
precipitation events will increase in
frequency and severity (Ch.
In weather systems, convergence
of increased water vapor leads to more intense
precipitation and the risk
of heavy rain and snow events, but may also lead to reductions in duration and / or
frequency of rain events, given that total amounts do not change much.
There are multiple studies associating extreme
precipitation events with waterborne disease outbreaks and strong climatological evidence for increasing
frequency and intensity
of extreme
precipitation events in the future.