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MAUSAM ◽  
2021 ◽  
Vol 65 (4) ◽  
pp. 585-590
Author(s):  
SUNILKUMAR PESHIN ◽  
DK CHAKRABORTY ◽  
SIDDHARTH SINGH

At present, climate change is a matter of great concern to mankind. This change, which is due to the manmade activities, is changing global temperature and the concentration of CO2 and O3 in the atmosphere. But there are some changes in the sun also. Solar changes could be assessed by solar flux at 10.7cm wavelength. Climate change could be assessed by long time temperature records. In this study we have examined whether solar change has any effect on climate change? We have analyzed two sets of data, 10.7cm solar flux (TSI) and global temperature record, along with total ozone, UV-B flux at ground and satellite data of total solar irradiance. Global temperature anomaly curve (GTAC) shows a slow increase of temperature up to about 1975 and a rapid rise after this year. Solar flux at 10.7cm wavelength shows a decreasing trend up to about 1970 and an increasing trend after this year. It also has 11 year cycle. GTAC, total ozone, UV-flux at ground and TSI also show 11 year cycle and some trend, but none of them matches the long-term trend found in solar flux at 10.7cm wavelength.


2021 ◽  
Author(s):  
Karsten Haustein

<p class="p1">The role of external (radiative) forcing factors and internal unforced (ocean) low-frequency variations in the instrumental global temperature record are still hotly debated. More recent findings point towards a larger contribution from changes in external forcing, but the jury is still out. While the estimation of the human-induced total global warming fraction since pre-industrial times is fairly robust and mostly independent of multidecadal internal variability, this is not necessarily the case for key regional features such as Arctic amplification or enhanced warming over continental land areas. Accounting for the slow global temperature adjustment after strong volcanic eruptions, the spatially heterogeneous nature of anthropogenic aerosol forcing and known biases in the sea surface temperature record, almost all of the multidecadal fluctuations observed over at least the last 160+ years can be explained without a relevant role for internal variability. Using a two-box response model framework, I will demonstrate that not only multidecadal variability is very likely a forced response, but warming trends over the past 40+ years are entirely attributable to human factors. Repercussions for amplifed European (or D-A-CH for that matter) warming and associated implications for extreme weather events are discussed. Further consideration is given to the communications aspect of such critical results as well as the question of wider societal impacts.</p>


2021 ◽  
Author(s):  
Guillermo Nicolás Murray Tortarolo

Earth’s surface temperature oscillated greatly throughout time. From near congelation during “snowball Earth” 2.9Gya to an ice-free world in the Paleocene-Eocene Thermal maximum 55Mya. These changes have been forced by internal (e.g. changes in the chemical composition of the atmosphere) or external (e.g. changes in solar luminosity) drivers that varied through time. Thus, if we understand how the radiation budget evolved in different times, we can closely calculate past global climate; a fundamental comparison to situate current climate change in the context Earth’s history. Here I present an analytical framework employing a simple energy balance derived from the Stephan-Boltzmann law, that allows for quick comparison between drivers of global temperature and at multiple moments in the history of our planet. My results show that current rates of increase in global temperature are at least four times faster than any previous warming event.


2021 ◽  
Author(s):  
Jorge Sánchez-Sesma

Abstract. This work provides a hypothesis of the links between the multi-millennia scale recurrent solar and tidal influences and Earth's climate lagged responses, associated with the oceanic transport mechanisms with a variable modulation. As a part of this hypothesis, empirical and simple, non-linear lagged models are proposed for five of the most representative Earth's climate variables (a continental tropical temperature, an Antarctic temperature [at James Ross Island], the Greenland temperature, the global temperature and the southeast asian monsoon) with multi-millennia records to account for the lagged responses to solar forcing. The proposed models implicitely include a well-known oceanic heat transport mechanism: the Ocean Conveyor Belt. This oceanic mechanism appears to generate a climate modulation through the intensity of the ocean/atmosphere circulation, and a heat and mass transport, with a consequent climate lag of several thousands of years. Tidal forcing is also considered for global temperature modelling and forecast. The consequent millennia-scale global forecasts, after being integrated/verified with an accumulated ocean travelled distance from the tropical East Pacific, and with a double evaluation of the tidal influences based on similarities and on the NASA’s solar system astronomical dynamics, indicates a cooling for the next century, and gentle oscillations over the next millennia. Our preliminary results that strongly suggest that millennial scale changes in solar activity induce circulation and thermal global impacts, also suggest that the Younger Dryas event, may be influenced by the lagged outcomes of solar driven changes in the tropical Pacific, and by tidal influences. The detected Earth's climate delayed responses, that have been working in the past and present climates, and will be working in the future climates, must be, as soon as possible, independently verified and theoretically sustained, before to be fully included in a multi-scale climate models as a scientific theory. A final example for the global temperature record over the last 170 years demonstrates with experimental results for the twenty first century evolution the convenience of a multi-scale climate modelling with contrasting lower values compared with the IPCC global temperature scenarios.


2021 ◽  
Author(s):  
Lukoye Atwoli ◽  
◽  
Abdullah H. Baqui ◽  
Thomas Benfield ◽  
Raffaella Bosurgi ◽  
...  
Keyword(s):  

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1584
Author(s):  
Purushottam D. Gujrati

The review deals with a novel approach (MNEQT) to nonequilibrium thermodynamics (NEQT) that is based on the concept of internal equilibrium (IEQ) in an enlarged state space SZ involving internal variables as additional state variables. The IEQ macrostates are unique in SZ and have no memory just as EQ macrostates are in the EQ state space SX⊂SZ. The approach provides a clear strategy to identify the internal variables for any model through several examples. The MNEQT deals directly with system-intrinsic quantities, which are very useful as they fully describe irreversibility. Because of this, MNEQT solves a long-standing problem in NEQT of identifying a unique global temperature T of a system, thus fulfilling Planck’s dream of a global temperature for any system, even if it is not uniform such as when it is driven between two heat baths; T has the conventional interpretation of satisfying the Clausius statement that the exchange macroheatdeQflows from hot to cold, and other sensible criteria expected of a temperature. The concept of the generalized macroheat dQ=deQ+diQ converts the Clausius inequality dS≥deQ/T0 for a system in a medium at temperature T0 into the Clausius equalitydS≡dQ/T, which also covers macrostates with memory, and follows from the extensivity property. The equality also holds for a NEQ isolated system. The novel approach is extremely useful as it also works when no internal state variables are used to study nonunique macrostates in the EQ state space SX at the expense of explicit time dependence in the entropy that gives rise to memory effects. To show the usefulness of the novel approach, we give several examples such as irreversible Carnot cycle, friction and Brownian motion, the free expansion, etc.


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