Variation in surface air temperature of China during the 20th century
The 20th century surface air temperature (SAT) records of China from various sources are analyzed using data which include the recently released Twentieth Century Reanalysis Project dataset. Two key features of the Chinese records are confirmed: (1) significant 1920s and 1940s warming in the temperature records, and (2) evidence for a persistent multidecadal modulation of the Chinese surface temperature records in co-variations with both incoming solar radiation at the top of the atmosphere as well as the modulated solar radiation reaching ground surface. New evidence is presented for this Sun–climate link for the instrumental record from 1880 to 2002. Additionally, two non-local physical aspects of solar radiation-induced modulation of the Chinese SAT record are documented and discussed.
Available from: Li Chunhui
- "Moreover, the Mann–Kendall (M-K) test, Sen's slope estimates, and wavelet transform analysis have also been used to detect and estimate trends in annual and seasonal temperature series and the relationships between temperature and other environmental factors (You et al. 2010; Soon et al. 2011). These various studies show that regional temperature variations are complex processes affected by numerous factors. "
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ABSTRACT: Under global climate change, the change in temperature has greatly affected the hydrological processes and water resource security in the source region of the Yellow River, which is located in the Qinghai-Tibet Plateau and serves as a major source of domestic and agricultural water supply in the watershed. Multiple spatiotemporal analysis methods, including the S-mode empirical orthogonal function analysis, the inverse distance weighted interpolation, the weighted moving average method, and the Mann-Kendall test method were used to comprehensively analyze the temperatures of 14 meteorological stations at yearly and seasonal scales from 1961 to 2010. The results indicated that (1) general trends of temperature change have been rising, with an especially significant warming trend since the late 1990s; (2) in the last five decades, temperature trends in the study area underwent three stages, namely a cool stage (approximately 1961-1980), a fluctuating stage (approximately 1981-1997), and a warm stage (approximately 1998-2010); and (3) due to the combined effects of monsoons and geographic features, the source region could be divided into three zones according to the annual temperature variations: a low-value zone centered on Henan station in the northeastern edge; a high-value zone situated in the central, southern, and western area; and a transitional zone between the two zones mentioned above. This study is helpful for understanding temperature trends under climate change and can provide a basis for ecological protection.
Available from: Victor Manuel Naumovich Velasco Herrera
- "To analyze local variations of power spectrum within a single non-stationary time series at multiple periodicities, such as UVB surface data and satellite data, the Morlet Wavelet is applied here because it provides higher resolution in the periodicity and because being a complex function allows us to analyze the evolution of periodicities in the time-space and to calculate the phase between two time series (Soon et al. 2011). "
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ABSTRACT: The measurement of solar B band Ultraviolet radiation (UVB) should be considered a priority in Mexico due to implications on public health throughout the country (total population, 108 million), but this is not carried out at present. Installed sensors cover only 0.12% of the country. However, there are alternative methods for estimating UVB radiation to overcome the lack of surface data. The most successful of these are based on the use of satellites for environmental monitoring. In the present work, UVB maps are constructed for the entire country using a single, daily satellite measurement of UVB at solar noon from 1978‒2003. Satellite-derived values are compared with the ground measurements by a surface station located in Mexico City in order to validate the former. Wavelet spectrum analysis
is employed to this end. A close correlation is observed between the two sets of data. Moreover, there is qualitative correspondence between the spatial distribution of the satellite-derived data and the surface topography. The difference resulting throughout the period mentioned is <2% of the average annual cumulative energy.
Available from: Nicola Scafetta
- "Indeed, the 60-year cyclicity with peaks in 1940 and 2000 appears quite more clearly in numerous regional surface temperature reconstructions that show a smaller secular warming trending. For example, in the United States (D'Aleo, 2011), in the Arctic region (Soon, 2009), in several single stations in Europe and other places (Le Moü el et al., 2008) and in China (Soon et al., 2011). In any case, a 60-year cyclical modulation is present for both the Norther and Southern Hemisphere and for both Land and "
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ABSTRACT: We compare the performance of a recently proposed empirical climate model
based on astronomical harmonics against all available general circulation
climate models (GCM) used by the IPCC (2007) to interpret the 20th century
global surface temperature. The proposed model assumes that the climate is
resonating with, or synchronized to a set of natural harmonics that have been
associated to the solar system planetary motion, mostly determined by Jupiter
and Saturn. We show that the GCMs fail to reproduce the major decadal and
multidecadal oscillations found in the global surface temperature record from
1850 to 2011. On the contrary, the proposed harmonic model is found to well
reconstruct the observed climate oscillations from 1850 to 2011, and it is able
to forecast the climate oscillations from 1950 to 2011 using the data covering
the period 1850-1950, and vice versa. The 9.1-year cycle is shown to be likely
related to a decadal Soli/Lunar tidal oscillation, while the 10-10.5, 20-21 and
60-62 year cycles are synchronous to solar and heliospheric planetary
oscillations. Finally, we show how the presence of these large natural cycles
can be used to correct the IPCC projected anthropogenic warming trend for the
21st century. By combining this corrected trend with the natural cycles, we
show that the temperature may not significantly increase during the next 30
years mostly because of the negative phase of the 60-year cycle. The same IPCC
projected anthropogenic emissions would imply a global warming by about 0.3-1.2
K by 2100, contrary to the IPCC 1.0-3.6 K projected warming. The results of
this paper reinforce previous claims that the relevant physical mechanisms that
explain the detected climatic cycles are still missing in the current GCMs and
that climate variations at the multidecadal scales are astronomically induced
and, in first approximation, can be forecast.
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