The 227-yr daily precipitation record gathered for Seoul, South Korea, represents one of the longest instrumental measurements, which provides an exceptional opportunity for detecting climate singularity (a property of phase locking to annual cycle) of extreme weather events and multidecadal–centennial variability of the rainy season structure. From late June to early September, the occurrence of heavy rain events shows a climatological quasi-biweekly oscillation. The rainy season characteristics, including the dates of onset, retreat, summit, and the duration, all show significant centennial variations. The rainy season summit shows a tendency toward delayed occurrence, which changed from the 37th pentad (P37; 30 June–4 July) during the 1778–1807 period to P44 (4–8 August) during the 1975–2004 period. The amplitude of the interannual (2–6 yr) variation of summer precipitation shows a prominent fluctuation with a 50-yr rhythm. A notable climatological break (around 9–13 August) divides the rainy season into a changma (Korean for continuous rain period) and a post-changma period. The major modes of subseasonal variability of the rainy season are characterized by an advanced changma and an enhanced post-changma, respectively. The former is dominated by biennial variation, whereas the latter has a major 5-yr spectral peak, suggesting that the processes leading to their variability are different. The occurrence of severe drought events exhibits a 4-yr spectral peak along with large power on a centennial time scale, while the severe flood events have a spectral peak at 3 and 19 yr, respectively. The remarkable climate variability in Seoul rainfall suggests that trends detected by using a 50-yr-or-shorter precipitation record likely reflect natural variability.

[1] Oceanic baroclinic modes in the equatorial Pacific are estimated using results from the SODA system. Our result suggests that the vertical stratification increases at the upper levels after the late 1970s due to changes in the vertical temperature structure. After the late 1970s, the variability of the higher-order baroclinic mode contributions to current anomalies and surface pressure significantly increases in the central equatorial Pacific. This is associated with an increase of the dominant period of the ENSO variability. Simple coupled model experiments indicate that when atmospheric forcing projects more onto the higher baroclinic modes according to the results of the SODA decomposition, the amplitude and dominant period of ENSO increase similarly to what is observed at the Pacific decadal shift. Our results support that the changes in the behavior of ENSO after the late 1970s are associated with oceanic vertical structural changes in temperature that tend to increase the contribution of higher-order baroclinic modes.INDEX TERMS: 3339

[1] The most striking features observed in the strong East Asian summer monsoon (EASM) are the seasonal change in the anomalous western North Pacific subtropical high (WNPSH) and the accompanying convective activities over the tropical Pacific and the Indian Ocean. The seasonal change in the anomalous WNPSH associated with the strong EASM has been studied through model experiments. The results of numerical experiments indicate that the anomalous WNPSH associated with the strong EASM has a strong seasonality with respect to its intensity and location. This is due to the difference between the contributions of the remote and local sea surface temperature forcings in the tropical Pacific and the Indian Ocean. It is also found that the air-sea interactions over the tropical western Pacific and the Indian Ocean are essential to appropriately simulate the intensity and location of the anomalous WNPSH, which in turn modulate the East Asian summer monsoon rainfall during the summer of the strong EASM years.

The Immersion Grating Infrared Spectrometer (IGRINS) is a compact high-resolution near-infrared cross-dispersed spectrograph whose primary disperser is a silicon immersion grating. IGRINS covers the entire portion of the wavelength range between 1.45 and 2.45μm that is accessible from the ground and does so in a single exposure with a resolving power of 40,000. Individual volume phase holographic (VPH) gratings serve as cross-dispersing elements for separate spectrograph arms covering the H and K bands. On the 2.7m Harlan J. Smith telescope at the McDonald Observatory, the slit size is 1ʺ x 15ʺ and the plate scale is 0.27ʺ pixel -1 . The spectrograph employs two 2048 x 2048 pixel Teledyne Scientific & Imaging HAWAII-2RG detectors with SIDECAR ASIC cryogenic controllers. The instrument includes four subsystems; a calibration unit, an input relay optics module, a slit-viewing camera, and nearly identical H and K spectrograph modules. The use of a silicon immersion grating and a compact white pupil design allows the spectrograph collimated beam size to be only 25mm, which permits a moderately sized (0.96m x 0.6m x 0.38m) rectangular cryostat to contain the entire spectrograph. The fabrication and assembly of the optical and mechanical components were completed in 2013. We describe the major design characteristics of the instrument including the system requirements and the technical strategy to meet them. We also present early performance test results obtained from the commissioning runs at the McDonald Observatory.

Various surface treatments on zirconia have been reported for dental porcelain veneer. However, it has not been determined which of these treatments provide the highest bond strength. The purpose of this study is to compare the effect of airborne particle abrasion and atmospheric pressure plasma treatment on the shear bond strength between zirconia and dental porcelain veneer. The groups were divided into four groups according to the surface treatment method: the control group, the atmospheric pressure plasma treated group (group P), the airborne particle abrasion group (group A), the atmospheric pressure plasma treated group after the airborne particle abrasion (group AP). Atmospheric pressure plasma was applied on the specimens using a plasma generator (Plasma JET, POLYBIOTECH Co. Ltd., Gwangju, Korea) and airborne-particle abraded with 110 µm. The characteristics of surface treated zirconia were analyzed by 3D-OP, XRD, XPS and contact angle. The shear bond strength was tested using a universal testing machine. The shear bond strength of group P was significantly increased compared to that of the control group (P < 0.05). The shear bond strength of group AP was significantly increased as compared to group A (P < 0.05). There was no significant difference between the group P and group A (P > 0.05). As a result of this study, the atmospheric pressure plasma treatment showed significantly higher shear bond strength than control group, but similar to the airborne particle abrasion, and the atmospheric pressure plasma treatment after the airborne particle abrasion provided the highest shear bond strength. This study demonstrated that application atmospheric pressure plasma treatment on zirconia may be useful for increasing bond strength between zirconia and dental porcelain veneer.