Urban Heat Islands (UHIs)

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Urban Heat Island Influence Inadequately Considered in Climate Research



Regions of the world that exhibit significant warming over recent decades [are] likely the result of a robust urban heat island effect…



The Urban Heat Island Effect Distorts Global Temperatures



[T]he three GAST [Global Average Surface Temperature] data sets are not a valid representation of reality.  In fact, the magnitude of their historical data adjustments, that removed their cyclical temperature patterns, are totally inconsistent with published and credible U.S. and other temperature data.  Thus, it is impossible to conclude from the three published GAST data sets that recent years have been the warmest ever – despite current claims of record setting warming.  Finally, since GAST data set validity is a necessary condition for EPA’s GHG/CO2 Endangerment Finding, it too is invalidated by these research findings.



Rampant, Glaringly Fraudulent Temp Monitoring Stations:

Study sponsored by NOAA finds that poorly-sited air temperature monitoring stations have artificially boosted global warming data



The NOAA-sponsored JAMS study confirmed what researchers have consistently maintained for years: Even relatively modest urban development near temperature recording devices can skew temperature measurements.



The number of weather stations providing data to GHCN [Global Historical Climatology Network] plunged in 1990 and again in 2005.  The sample size has fallen by over 75% from its peak in the early 1970s, and is now smaller than at any time since 1919.  The collapse in sample size has not been spatially uniform.  It has increased the relative fraction of data coming from airports to about 50 percent (up from about 30 percent in the 1970s).  It has also reduced the average latitude of source data and removed relatively more high-altitude monitoring sites.  GHCN applies adjustments to try and correct for sampling discontinuities.  These have tended to increase the warming trend over the 20th century…  The quality of data over land, namely the raw temperature data in GHCN, depends on the validity of adjustments for known problems due to urbanization and land-use change.  The adequacy of these adjustments has been tested in three different ways, with two of the three finding evidence that they do not suffice to remove warming biases…  The overall conclusion of this report is that there are serious quality problems in the surface temperature data sets that call into question whether the global temperature history, especially over land, can be considered both continuous and precise.



Anomalies from satellite data and surface-station data have been increasing in the last 3 decades  The Klotzbach [et al, 2009]  paper  finds that the divergence between surface and lower tropospheric trends is consistent with evidence of a warm bias in the surface temperature record but not in the satellite data…  According to the WMO’s own criteria, followed by the NOAA’s National Weather Service, temperature sensors should be located on the instrument tower at 1.5 m (5 feet) above the surface of the ground.  The tower should be on flat, horizontal ground surrounded by a clear surface, over grass or low vegetation kept less than 4 inches high.  The tower should be at least 100 m (110 yards) from tall trees, or artificial heating or reflecting surfaces, such as buildings, concrete surfaces, and parking lots.  Very few stations meet these criteria… [because w]eather data from cities as collected by meteorological stations are indisputably contaminated by urban heat-island bias and land-use changes.



After pointing out an airplane got stuck in heat softened asphalt, Al Gore misses the fact that many of the surface temperatures used in climate come from airports


… &

Two-thirds of the [world’s ‘official’ temperature monitoring] stations are at airports and they show regular divergences from the non-airport stations…



What Anthony Watts and Evan Jones have revealed [about false temperature monitoring] is breathtaking, a must see.  Half of the [global] warming trend has gone.   92% of the artificial rise was due to ‘erroneous adjustments of well sited stations.’   Muller et al used an older siting classification system.  The new classification system shows that siting does have a major impact on the [surface temperature] data.



A recent study by Menne et al. [2010] used a preliminary classification from the Surface Stations Project, including 40% of the USHCNv2 stations. Approximately one third of the [U.S.] stations previously classified as good exposure sites were subsequently reevaluated and found to be poorly sited…  Because so few USHCNv2 stations were actually found to be acceptably sited, the sample size at 40% was not fully spatially representative of the continental USA…  The comparison of time series of annual temperature records from good and poor exposure sites shows that differences do exist between temperatures and trends calculated from USHCNv2 stations with different exposure characteristics…  [W]e found the raw (unadjusted) minimum temperature trend to be significantly larger when estimated from the sites with the poorest exposure sites relative to the sites with the best exposure…  Overall, this study demonstrates that station exposure does impact USHCNv2 temperatures.  The temperatures themselves are warmest compared to independent analyses at the stations with the worst siting characteristics.  Temperature trend estimates vary according to site classification, with poor siting leading to an overestimate of minimum temperature trends…



Record Temperature Readings Throughout Los Angeles Caused By ‘Faulty Weather Stations,’ Meteorologist Says



Annual daytime and nighttime surface urban heat island intensity (SUHII) increased significantly [between 2001 and 2017 and, most surprisingly] the effect of greening in rural areas was a significant and widespread driver for the increased daytime SUHII [globally].





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