ENSO Amplitude Modulation Associated with the Mean SST Changes in the Tropical Central Pacific Induced by Atlantic Multidecadal Oscillation

Abstract The mechanism associated with the modulation of the El Niño–Southern Oscillation (ENSO) amplitude caused by the Atlantic multidecadal oscillation (AMO) is investigated by using long-term historical observational data and various types of models. The observational data for the period 1900–2013 show that the ENSO variability weakened during the positive phase of the AMO and strengthened in the negative phase. Such a relationship between the AMO and ENSO amplitude has been reported by a number of previous studies. In the present study the authors demonstrate that the weakening of the ENSO amplitude during the positive phase of the AMO is related to changes of the SST cooling in the eastern and central Pacific accompanied by the easterly wind stress anomalies in the equatorial central Pacific, which were reproduced reasonably well by coupled general circulation model (CGCM) simulations performed with the Atlantic Ocean SST nudged perpetually with the observed SST representing the positive phase of the AMO and the free integration in the other ocean basins. Using a hybrid coupled model, it was determined that the mechanism associated with the weakening of the ENSO amplitude is related to the westward shift and weakening of the ENSO zonal wind stress anomalies accompanied by the westward shift of precipitation anomalies associated with the relatively cold background mean SST over the central Pacific

Contribution of Synoptic Transients to the Potential Predictability of PNA Circulation Anomalies: El Niño versus La Niña

Abstract The potential predictability (PP) of seasonal-mean 200-hPa geopotential height (Z200) anomalies in the Pacific–North American (PNA) region is examined for El Niño and La Niña separately by using 50 ensemble members of twentieth-century AGCM simulations. Observed sea surface temperature (SST) is prescribed for the period 1870–2009, and 14 El Niño and La Niña years after 1900 are selected for the present study. The domain-averaged value of PP for Z200 in the PNA region, as measured by the signal-to-noise ratio, for El Niño is about 60% larger than that of La Niña. Such a large PP is mainly due to a larger signal and partly to less noise during El Niño compared to that during La Niña . The transient eddy feedback to the PNA circulation anomalies is stronger during El Niño events (about 50%) than that during La Niña, and this difference in the transients contributes significantly to the different Z200 signals in the PNA region. The noise variance of the transients during El Niño is about 17% smaller than during La Niña, and thus transients play an important role in the reduction of Z200 noise during El Niño. Idealized experiments with the same spatial pattern but different signs of SST anomalies confirm the results mentioned above. Moreover, these experiments with several different amplitudes of positive and negative phases of tropical Pacific SST anomalies show that signals of Z200 and transients are proportional to precipitation anomalies in the tropical Pacific, and noises of Z200 for El Niño cases are somewhat smaller than the corresponding values of La Niña

Multidecadal Changes in the Relationship between ENSO and Wet-Season Precipitation in the Arabian Peninsula

Abstract Multidecadal variations in the relationship between El Niño–Southern Oscillation (ENSO) and the Arabian Peninsula rainfall are investigated using observed data for the last 60 years and various atmospheric general circulation model (AGCM) experiments. The wet season in the Arabian Peninsula from November to April was considered. The 6-month averaged Arabian rainfall was negatively correlated with ENSO for an earlier 30-yr period from 1950 to 1979 and positively correlated to ENSO for a more recent period from 1981 to 2010. The multidecadal variations can be attributed to the variations in Indian Ocean SST anomalies accompanied by ENSO. In the early 30-yr period, ENSO accompanied relatively large SST anomalies in the Indian Ocean, whereas in the recent 30-yr period it accompanied relatively small SST anomalies in the Indian Ocean. The atmospheric anomalies in the Arabian region during ENSO are combined responses to the Pacific and Indian Ocean SST anomalies, which offset each other during ENSO. The recent El Niño events accompanied negative 200-hPa geopotential height (GH) anomalies over the Arabian region, mainly forced by the Pacific SST anomalies, resulting in an increase of precipitation over the region. In contrast, in the early 30-yr period, Indian Ocean SST anomalies played a dominant role in the atmospheric responses over the Arabian region during ENSO, and the negative GH anomalies and more precipitation over the Arabian region were mainly forced by the negative SST anomalies over the Indian Ocean, which appeared during La Niña. These observed findings are confirmed by various AGCM experiments

On the Need of Intermediate Complexity General Circulation Models: A "SPEEDY" Example

processes that allows realistic and fast climate simula -tions that often involve large ensembles for the purpose of reducing uncertainty and estimation of the forced and internal variability of the system. The forced signal is typically estimated by an ensemble mean of many simulations, but ensembles of state-of-the-art models are often too small to reduce the remaining internal variability. The ensemble size needed to estimate the mean accurately depends on the signal-to-noise ratio for the variable and region under consideration. For example, the ensemble size to estimate midlatitude 500-hPa height accurately is about 20, which is larger than most ensembles used in seasonal hindcast data-sets or climate projections performed by individual centers. Intermediate complexity models can also be used efficiently to investigate the sensitivity of simu-lated climate to changes in parameters in the physical parameterizations. Another application is related to climate change. For example, Forest et al. (2002) and Sokolov at al. (2009) use the MIT Integrated Global System Model (MIT IGSM) to investigate topics such as climate sensitivity, aerosol forcing, ocean heat uptake rate, and probabilistic projections of climate change. There are many intermediate complexity system models of intermediate complexity (EMICs). A number of them are participating in the IPCC Fifth Assessment Report and can be found at http://climate .uvic.ca/EMICAR5 (one of which is based on a previous version of the model introduced here). This website also provides information about experiments that are performed with these models that range from en-sembles of 1,000-year-long historical simulations to the assessment of different C

Analysis of Changes in the Total Lymphocyte and Eosinophil Count during Immunotherapy for Metastatic Renal Cell Carcinoma: Correlation with Response and Survival

The aims of this study were to analyze lymphocyte and eosinophil counts in consecutive peripheral blood samples taken during immunotherapy for metastatic renal cell carcinoma (mRCC) and to correlate the findings with objective response and survival. A total of 40 patients with mRCC who received immunotherapy with interleukin-2, interferon-α, and 5-fluorouracil were analyzed. Objective responses were observed in 14 patients, including 2 (5%) who showed a complete response (CR) and 12 (30%) who showed a partial response (PR). Eleven patients (27%) achieved stable disease (SD), and 15 patients (38%) had progressive disease (PD). Changes from baseline in the total lymphocyte counts were significantly higher in the responding patients (CR+PR+SD) than in the non-responding patients (PD) (p=0.017), but no difference was seen in the total eosinophil counts (p=0.275). Univariate analysis identified the Eastern Cooperative Oncology Group (ECOG) performance status (p=0.017), the presence of a primary renal tumor (p<0.001) and the peripheral lymphocyte counts at week 4 (p=0.034) as prognostic factors, but a low ECOG performance status (p=0.003) and the presence of a primary renal tumor (p=0.001) were identified as independent poor prognostic factors by multivariate analysis. This study provides further evidence that changes in blood lymphocyte counts may serve as an objective indicator of objective responses

Defining the Optimal Time of Adaptive Replanning in Prostate Cancer Patients with Weight Change during Volumetric Arc Radiotherapy: A Dosimetric and Mathematical Analysis Using the Gamma Index

We evaluated the changes in the dose distribution of radiation during volumetric arc radiotherapy (VMAT), to determine the right time for adaptive replanning in prostate cancer patients with progressive weight (WT) changes. Five prostate cancer patients treated with VMAT were selected for dosimetric analysis. On the original computed tomography images, nine artificial body contours were created to reflect progressive WT changes. Combined with three different photon energies (6, 10, and 15-MV), 27 comparable virtual VMAT plans were created per patient. The dosimetric analysis included evaluation of target coverage (D95%,Dmax), conformity index, homogeneity index, and organs at risk doses. The dose differences among the plans were determined using the gamma index analysis and were compared with the dosimetric analysis. Mean D95% became lower than 98% when body contour expanded by 2.0 cm or more and Dmax became higher than 107% when body contour contracted by 1.5 cm or more in 10-MV plans. This cut-off values correlated well with gamma index analysis results. Adaptive replanning should, therefore, be considered if the depth of body contour becomes 1.5 cm smaller (WT loss) or 2.0 cm larger (WT gain) in patients treated by VMAT with 10-MV photons

Influence of Diaphragmatic Mobility on Hypercapnia in Patients with Chronic Obstructive Pulmonary Disease

A reduction in diaphragm mobility has been identified in patients with chronic obstructive pulmonary disease (COPD) and has been associated with a decline in pulmonary function parameters. However, little information exists regarding the potential role of diaphragm mobility on hypercapnia in COPD. A new method of assessing the mobility of the diaphragm, using ultrasound, has recently been validated. The purpose of the present study was to investigate the relationship between diaphragm mobility and pulmonary function parameters, as well as that between arterial blood gas values and diaphragm mobility, in COPD patients. Thirty seven COPD patients were recruited for pulmonary function test, arterial blood gas analysis and diaphragm mobility using ultrasound to measure the craniocaudal displacement of the left branch of the portal vein. There were significant negative correlations between diaphragmatic mobility and PaCO2 (r = -0.373, P = 0.030). Diaphragmatic mobility correlated with airway obstruction (FEV1, r = 0.415, P = 0.011) and with ventilatory capacity (FVC, r = 0.302, P = 0.029; MVV, r = 0.481, P = 0.003). Diaphragmatic mobility also correlated significantly with pulmonary hyperinflation. No relationship was observed between diaphragm mobility and PaO2 (r = -0.028, P = 0.873). These findings support a possibility that the reduction in diaphragm mobility relates to hypercapnia in COPD patients