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The properties and dependences of lower tropospheric geopotential height (GPH) and relative vorticity extreme values are investigated in high spatial resolution ERA-Interim reanalysis data during the boreal winters from 1980-2014. A peak-over-threshold (POT) analysis is applied to determine the local generalized Pareto distribution (GPD) parameters with a 90th percentile threshold. In Northern Hemispheric storm tracks, the scale parameter decreases along the storm track axis for vorticity, whereas it increases for GPH. The shape parameters are weakly negative for both fields in the northern midlatitudes and over land, suggesting upper bounds for the extremes. The blackassociation of GPD parameters blackwith the large-scale flow is assessed using monthly mean indices for the North Atlantic Oscillation (NAO), Pacific-North American (PNA) pattern and El Niño Southern Oscillation (Nino3.4 index) as covariates. blackWhile the GPH parameters are related to the covariates in the regions associated with the covariate loadings, the vorticity parameters are weakly related to all covariates. It is noteworthy that the NAO dominates all covariates in the central tropical Pacific. The probability for concurrent extreme events of vorticity and GPH is highest in storm tracks with values of about 0.3-0.5. [ABSTRACT FROM AUTHOR]

The article presents a study on sea surface temperature (SST) reconstruction for terrestrial Holocene climate. It states that Planet Simulator, an intermediate complexity Earth System model was used to carry out climate simulation. It mentions that the sensitivities of the terrestrial PlaSim climate was determined with SST anomalies to provide climate simulation that reflects the proxy-derived climate during the Holocene.

The co-operative effects of volcanic eruptions and ENSO (El Niño/Southern Oscillation) on the climate in China are analyzed in a millennium simulation for 800-2005 AD using the earth system model (ESM) ECHAM5/MPIOM/JSBACH subject to anthropogenic and natural forcings. The experiment includes two ensembles with weak (5 members) and strong (3 members) total solar irradiance variability. In the absence of El Niño and La Niña events, volcanoes, which are the dominant forcing in both ensembles, cause a dramatic cooling in West China (-2°C) and a drought in East China during the year after the eruption. The recovery times for the volcano induced cooling vary globally between one and 12 yr; in China these values are mostly within 1-4 yr, but reach 10 yr in the Northeast. Without volcanoes, after El Niño events the summer precipitation is reduced in the North, while South China becomes wetter (indicated by the Standardized Precipitation Index, SPI, for summers, JJA); La Niña events cause opposite effects. El Niño events in the winters after eruptions compensate the cooling in most regions of China, while La Niña events intensify the cooling (up to -2.5°C). The simulated impact of the eruption of the Tambora in 1815, which caused the "year without summer" 1816 in Europe and North America and coldness and famines for several years in the Chinese province Yunnan, depends crucially on the ENSO state of the coupled model. A comparison with reconstructed El Niño events shows a moderate cool climate with wet (in the South) and extreme dry anomalies (in the North) persisting for several years. [ABSTRACT FROM AUTHOR]

The article presents a research study concerning the 1/f-noise measurement and its significance in climate and weather observations in Yangtze River, China. Researchers cited the usefulness of such measurement in determining the variations and spectrum of humidity, precipitation, temperature, and wind speed. The river's high volatility and its intra-annual 1/f spectrum is also determined.

The atmosphere gains available potential energy by solar radiation and dissipates kinetic energy mainly in the atmospheric boundary layer. We analyze the fluctuations of the global mean energy cycle defined by Lorenz in a simulation with a simplified hydrostatic model. The energy current densities are well approximated by the generalized Gumbel distribution and the Generalized Extreme Value (GEV) distribution. In an attempt to assess the fluctuation relation of Evans, Cohen, and Morriss we define entropy production by the injected power and use the GEV location parameter as a reference state. The fluctuation ratio reveals a linear behavior in a finite range.

The 1/f spectrum of the ocean surface temperature in the Atlantic and Pacific midlatitudes is explained by a simple vertical diffusion model with a shallow mixed layer on top of a deep ocean. The model is forced at the air-sea interface with the total surface heat flux from a 1000 year climate simulation. The analysis reveals the role of ocean advection and substantiates estimates of internal thermal diffusivities.

Power-law scaling of near surface air temperature fluctuations and its geographical distribution is analyzed in 100-yr observations and in a 1000-yr simulation of the present-day climate with a complex atmosphere-ocean model. In observations and simulation detrended fluctuation analysis leads to the scaling exponent alpha approximately 1 over the oceans, alpha approximately 0.5 over the inner continents, and alpha approximately 0.65 in transition regions [spectrum S(f) approximately f(-beta),beta=2alpha-1]. Scaling up to decades is demonstrated in observations and coupled atmosphere-ocean models with complex and mixed-layer oceans. Only with the complex ocean model the simulated power laws extend up to centuries.

A renormalization group analysis is applied to autoregressive processes with an infinite series of coefficients. A simple fixed point is given by a random walk, and a second class is found that is proportional to the high order coefficients of fractional autoregressive integrated moving average (ARIMA) processes. The approach might be useful to detect nonstationarity in autoregressive processes.

Patient wait times are inevitable, but their reduction or elimination is an important marketing tool. Patients feel increased time demands, and if the wait is too long, they may not come back. However, if wait times are reasonable and handed well, patients are more likely to have a positive perception of services and return to the practice. In this article, the authors review the reality of wait times in medical practices today, sources of patient dissatisfaction with wait times, the treatment patients want while waiting, and a checklist of steps to reduce wait times.