Saturday, October 27, 2007


SOLAR VARIABILITY, COUPLING, AND CLIMATE

There are a number of ways the sun effects climate.
-A change in the solar constant of (wavelength) irradiance output.
-Changes in ultraviolet irradiance that modulates temperature, atmospheric chemistry, and climatic dynamics such as precipitation and cloud formation .
-Indirect and indirect influences by solar radiation and cosmic radiation(galactic)
-Changes in magnetic and gravitational constants(solar).
-Changes in magnetic connections heliospherical couplings

There are a number of flawed assumptions on the adequacy of GCM models to accurately reflect the exogenous variable forcings such as solar. The assumed parameters of solar variance are normally based on the infrared oscillations or the seasonal oscillations of direct heat(w/m2) and vertical energy transport. Measurements and analysis is usually undertaken on 1 or 2 parameters and the simplistic models used in GCM do not reflect the observations.

The solar activity in all its manifestations is subject to regular and irregular chaotic variations in quite large ranges of amplitudes, durations, and other characteristics that have revealed themselves some way in the time intervals under analysis. This general rule does not exclude coronal mass ejections and flares, which represent with respect to each other not the cause and effect (sometimes, such an unjustified assumption is made),but rather two observable manifestations of a single dissipative process related to an increased transport of free energy from the interiors of the Sun outwards into its upper atmosphere and heliosphere and dispersal into space and the solar system. This free energy is redistributed in thermal, magnetic, kinetic, gravitational, and radiation forms, their relative fractions being changed from event to event depending on the situation determined by the boundary conditions and initial state.

The inadequacy of analysis to review long term orbital parameters(long frequency)or short term(short frequency) such as the 11 year cycle or the suns 27 day rotational cycle or indeed the energetic upper atmosphere ionisation during solar events(x-ray flaring) Previous observations and modeling of the responses of planetary ionospheres to changes in solar flux have generally compared solar maximum and minimum conditions. Varying solar fluxes also modify the neutral atmosphere,and thus ionospheric changes result from two highly coupled processes. Changes in photon flux due to a flare from far slower changes in the neutral atmosphere, thereby providing a way to constrain or liberate photochemistry. This is particularly important for x-ray photons that carry energy far above that needed to ionize an atom or molecule(around 2.5 magnitudes,a single photon with an energy value of around 36kev can ionize around 200000 molecules.). In such cases, the electron liberated by ionization has so much extra energy that it ionizes other atoms and molecules via collisions. This secondary ionization by photoelectrons has an amplification effect on upper atmosphere chemical genesis (thermo diffusion).

Indeed as an x-ray photon enters a water molecule for example, it severs the chemical bonds,the component parts of the water molecule,which in the presence of O2 form hydrogen and hydroxyl radicals ,super oxide ions, and hydrogen peroxide. The process also releases substantial energy as thermal emissions.

Some progress has been made by the SPARC group of the WCRP, mostly by the SOLICE group and Haigh et al. Examples such as the 8 k differential in solar minima-maxima forcings and vertical profiling of temperature gradients are improvements. However insertion of CCM models into standard GCM is not a standard assimilation.

Other progress has been made by the Climate research group (Schelisinger, Andronova, et al) and Rozanov .Also work by the FUB reflects some progress with solar variance and photochemical assimilation.Solar UV is as important as IR solar output in conjunction with a CCM they find that intergration of TSI (solar irriadiance), Solar UV and the effects of solar energetic precipitation during changes from solar minima to maxima have significant photochemistry effects.

SUV findings
-Ozone increases by 3% in the upper stratosphere and 2% in the lower stratosphere.
-Warming of 1.2 K in the stratosphere and acceleration of both polar night jets.
-Simulated zonal wind and temperature response reproduces the observed downward and -poleward propagation.
Weak wave driving (mostly in SH):
- waves refracted into subtropics
- strong polar night jet
- cold polar stratosphere
- polar chemical ozone loss and reduced
ozone transport (weak BD circulation)

High wave driving (mostly in NH)
- wave propagation towards pole
- weak polar vortex
- warm polar stratosphere
- enhanced ozone transport & reduced
polar chemical ozone loss (strong BD
circulation

Rozanov et al

It was shown by Hood [2004], Rozanov et al. [2004],and Egorova et al. [2004] that the simulated responses of ozone and temperature to solar irradiance variation over the 11-year solar cycle do not agree with the solar signal extracted from the observational data. This discrepancy could be due to insufficient data not allowing the extraction of the solar signal with sufficient accuracy or due to physical and/or chemical mechanisms missing in the Chemistry-Climate models (CCMs). Energetic electron precipitation (EEP) events leading to enhanced NOy (NOy = NO +NO2 + NO3 + HNO3 + ClNO3 + 2*N2O5 + HNO4) is one potential candidate. These events have been shown to substantially alter stratospheric chemistry. The EEP mechanism has been proposed by Callis et al. [1998]. Electrons trapped in the outer radiation belt of the Earth’s magnetosphere,stimulated by the high-speed solar wind, are accelerated and can, after precipitation, penetrate into the atmosphere over the auroral and sub-auroral regions. They ionize neutral components providing a source of reactive nitrogen and hydrogen. During the cold season total reactive nitrogen may descend into the stratosphere destroying ozone and affecting the entire atmosphere. Measurements show that EEP events are more frequent and intense during the declining phase of solar activity, when coronal holes migrate towards the solar equator and the solar wind is more nearly directed toward Earth. This fact is supported by satellite observations [Callis et al., 1998] and by observations of precipitation events measured in the Murmansk region [Bazilevskaya et al., 2002].

From these results we draw the following conclusions.The simulated influence of EEP on the atmosphere consists of reactive nitrogen enhancement, ozone depletion,and cooling almost in the entire stratosphere. Effects are most pronounced over high latitudes and intensify the polar vortices resulting in the SATs increasing over Europe,Russia and the U.S. by up to 2.5 K during boreal winter.

Potentially, EEP effects on ozone and temperature are stronger than the influence of solar irradiance. The intensity of EEP is most pronounced during the declining phase of the solar activity cycle, that is, closer to solar activity minimum, therefore all effects mentioned here should be approximately reversed if we compare solar maximum relative to solar minimum. This means that EEP and UV mechanisms work in phase in the extra-polar stratosphere, but out of phase over the high latitudes and in the troposphere. The polar vortices are more intense for the solar maximum case due to the enhanced solar irradiance, but less intense due to EEP.

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