GISS Analysis of Surface Temperature Changes

We describe the current GISS analysis of surface temperature change based primarily on meteorological station measurements. The global surface temperature in 1998 was the warmest in the period of instrumental data. The rate of temperature change is higher in the past 25 years than at any previous time in the period of instrumental data. The warmth of 1998 is too large and pervasive to be fully accounted for by the recent El Nino, suggesting that global temperature may have moved to a higher level, analogous to the increase that occurred in the late 1970s. The warming in the United States over the past 50 years is smaller than in most of the world, and over that period there is a slight cooling trend in the Eastern United States and the neighboring Atlantic ocean. The spatial and temporal patterns of the temperature change suggest that more than one mechanism is involved in this regional cooling

MATRIX (Multiconfiguration Aerosol TRacker of mIXing state): an aerosol microphysical module for global atmospheric models

A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS) climate model (ModelE) are described. This module, which is based on the quadrature method of moments (QMOM), represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations. <br><br> A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment. This is more likely due to oversimplifications of the representation of sea salt emissions – sea salt emissions are only calculated for two size classes – than to inherent limitations of MATRIX

Total aerosol effect: forcing or radiative flux perturbation

Uncertainties in aerosol radiative forcings, especially those associated with clouds, contribute to a large extent to uncertainties in the total anthropogenic forcing. The interaction of aerosols with clouds and radiation introduces feedbacks which can affect the rate of precipitation formation. In former assessments of aerosol radiative forcings, these effects have not been quantified. Also, with global aerosol-climate models simulating interactively aerosols and cloud microphysical properties, a quantification of the aerosol forcings in the traditional way is difficult to define properly. Here we argue that fast feedbacks should be included because they act quickly compared with the time scale of global warming. We show that for different forcing agents (aerosols and greenhouse gases) the radiative forcings as traditionally defined agree rather well with estimates from a method, here referred to as radiative flux perturbations (RFP), that takes these fast feedbacks and interactions into account. Based on our results, we recommend RFP as a valid option to compare different forcing agents, and to compare the effects of particular forcing agents in different models

Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the largescale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF) calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016Wm⁻². Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18Wm⁻² higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in a slightly stronger response per unit forcing during later decades. Tropical precipitation shifts south during boreal summer from 1850 to 1970, but then shifts northward from 1970 to 2000, following upper tropospheric temperature gradients more strongly than those at the surfac

A cross‐sectional view of the current state of treatment of youth with type 2 diabetes in the USA: enrollment data from the Pediatric Diabetes Consortium Type 2 Diabetes Registry

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136377/1/pedi12377_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136377/2/pedi12377.pd

Vitamin D status in youth with type 1 and type 2 diabetes enrolled in the Pediatric Diabetes Consortium (PDC) is not worse than in youth without diabetes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134500/1/pedi12340.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134500/2/pedi12340_am.pd

Race, Socioeconomic Status, and Treatment Center Are Associated with Insulin Pump Therapy in Youth in the First Year Following Diagnosis of Type 1 Diabetes

Background: Increasing numbers of children and adolescents with type 1 diabetes (T1D) have been placed on insulin pump therapy. Nevertheless, data are limited regarding patterns of pump use during the first year of treatment and the clinical and socioeconomic factors associated with early use of pump therapy. Therefore, we sought to determine factors associated with pump therapy within the first year of diagnosis in youth enrolled in the Pediatric Diabetes Consortium (PDC) T1D New-Onset (NeOn) Study. Subjects and Methods: The NeOn Study includes youth <19 years old at T1D diagnosis who have been followed from the time of diagnosis at seven U.S. pediatric diabetes centers. Cox regression was used to determine factors associated with transition from injection to pump therapy during the first year of T1D in 1,012 participants. Results: Twenty-seven percent (n=254) of participants began pump therapy within the first year of diagnosis, ranging from 18% to 59% among the seven centers. After adjusting for center effect, factors associated with pump use in multivariate analysis included private health insurance (37% vs. 7%; P<0.001), having annual household income over $100,000 (50% vs. 15%; P<0.001), and non-Hispanic white race (36% vs. 11%; P<0.001). The hemoglobin A1c level did not appear to influence the decision to initiate pump use. Conclusions: Participants of non-Hispanic white race and higher socioeconomic status were more likely to be placed on pumps during the first year. Further investigations are needed to gain a better understanding of barriers to use of pumps in youth with T1D, especially in disadvantaged and minority families.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140353/1/dia.2013.0132.pd

Evidence for Planet-induced Chromospheric Activity on HD 179949

We have detected the synchronous enhancement of Ca II H & K emission with the short-period planetary orbit in HD 179949. High-resolution spectra taken on three observing runs extending more than a year show the enhancement coincides with phi ~ 0 (the sub-planetary point) of the 3.093-day orbit with the effect persisting for more than 100 orbits. The synchronous enhancement is consistent with planet-induced chromospheric heating by magnetic rather than tidal interaction. Something which can only be confirmed by further observations. Independent observations are needed to determine whether the stellar rotation is sychronous with the planet's orbit. Of the five 51 Peg-type systems monitored, HD 179949 shows the greatest chromospheric H & K activity. Three others show significant nightly variations but the lack of any phase coherence prevents us saying whether the activity is induced by the planet. Our two standards, tau Ceti and the Sun, show no such nightly variations.Comment: 10 pages, 6 figures. Submitted to Ap