[1] We have introduced additional NO y sources caused by energetic electron precipitation (EEP) during 1987 into a Chemistry-Climate model. Comparison of two model runs with and without EEP reveals increase of reactive nitrogen by about 2 ppbv in the middle stratosphere over the tropical and middle latitudes. In the upper stratosphere over the polar winter regions the simulated NO y enhancement reaches 10 ppbv. Decreases of the ozone mixing ratio in the stratosphere by up to 5% over midlatitudes and up to 30% over southern high-latitudes are calculated. A $0.5 K cooling in the middle stratosphere over the tropics and up to 2 K over southern high-latitudes is calculated with detectable changes in the surface air temperatures. These results confirm that the magnitude of the atmospheric response to EEP events can potentially exceed the effects from solar UV fluxes. These mechanisms work in phase outside polar latitudes, but can compensate each other within polar latitudes. Citation: Rozanov, E., L. Callis, M. Schlesinger, F. Yang, N. Andronova, and V. Zubov (2005), Atmospheric response to NO y source due to energetic electron precipitation, Geophys. Res. Lett., 32, L14811,

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The problem concerning the greenhouse effects of human activities has broadened in scope frbm the CO2-climate problem to the trace gas-climate problem. The climate effects of non-CO 2 trace gases are strongly governed by interactions between chemistry, radiation, and dynamics. We discuss in delfiil the natuie of the trace gas radiative heating and describe the importance of radiative-chemical interactions within the troposphere and the stratosphere. We make an assessment of the trace gas effects on troposphere-stratosphere temperature trends for the period covering the preindustrial era to the present and for the next several decades. Non-CO 2 greenhouse gases in the atmosphere are now adding to the greenhouse effect by an amount comparable to the effect of CO 2. The rate of decadal increase of the total greenhouse forcing is now 3-6 times greater than the mean rate for th where it is the climate feedback parameter and •: is the effective ocean thermal diffusivity. Th• magnitude of it, which also governs the equilibrium surface warming, is governed strongly by radiative and dynaniical processes in the atmosphere, and hence the effect of oceans on transient climate change is determined by the interactions between atmospheric and oceanic dynamical as well as radiative processes. The next crucial issue concerns accurate determination of decadal trends in radiative forcings, trace gases, planetary albedo (to determine effects of aerosols and cloud feedback), and surface-troposphere-stratosphere temperatures. The observational challenges are formidable and must be overcome for a scientifically credible interpretation of the human impacts on climate.

Abstract.A geoeffective magnetic cloud impacted the Earth early on 15 May 1997. The cloud exhibited strong initial southward interplanetary magnetic field (Bz--25 nT), which caused intense substorm activity and an intense geomagnetic storm (Dst--170 nT). SAMPEX data showed that relativistic electrons (E _> 1.0 MeV) appeared suddenly deep in the magnetosphere at L=3 to 4• These electrons were not directly "injected" from higher altitudes (i.e., from the magnetotail), nor did they come from an interplanetary source. The electron increase was preceded (for-2 hrs) by remarkably strong low-frequency wave activity as seen by CANOPUS ground stations and by the GOES-8 spacecraft at geostationary orbit. POLAR/CEPPAD measurements support the result that high-energy electrons suddenly appeared deep in the magnetosphere. Thus, these new multi-point data suggest that strong magnetospheric waves can quickly and efficiently accelerate electrons to multi-MeV energies deep in the radiation belts on timescales of tens of minutes.

Abstract-The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from -1 to -30 MeV and H and He nuclei from -20 to -300 MeV/nuc, with isotope resolution of H and He extending from -20 to -80 MeVlnuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect 0 3 depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy ( Z > 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.