Uncertainties in cloud feedback remain stubbornly significant in global climate models, disrupting the credibility of climate projections. This study examined the impacts of the prognostic treatment ...of precipitation on cloud feedback using the Model for Interdisciplinary Research on Climate version 6 (MIROC6). In a prognostic precipitation scheme, precipitating hydrometers are explicitly predicted, allowing a more sophisticated representation of their microphysical and radiative effects than that of traditional diagnostic schemes. The introduction of the prognostic scheme in MIROC6 increases cloud feedback associated with the elevated altitude of clouds in warming climates. Moreover, the equilibrium climate sensitivity increases by about 20%. Because associated high‐level clouds are better represented in the prognostic scheme, climate projections with larger altitude feedback are considered more credible. Additional analyses of Coupled Model Intercomparison Project models suggests that their altitude cloud feedback would be higher if their underestimation of high‐level clouds were mitigated.
Plain Language Summary
Uncertainties in global mean temperature projections are primarily associated with the spread in cloud feedback across models, which accelerate or decelerate global warming through cloud sunshade and/or greenhouse effects. A possible reason for the spread in cloud response is the overly simplified treatment of precipitation in models, where rain and snow particles immediately fall from the atmosphere down to the surface within a single model time interval of about 10 min. Here, we introduced a more sophisticated precipitation scheme that explicitly calculates the physical processes of falling rain and snow particles, thus preserving their “memory” in the atmosphere with their sunshade and greenhouse effects incorporated. As a result, the representation of clouds is significantly improved in this model, and greenhouse effects by clouds in warming climates are significantly enhanced. This study lends credence to higher cloud feedback and climate sensitivity if models incorporate the missing feedback processes in line with observational constraints.
Key Points
Acceleration of global warming by cloud altitude feedback is enhanced in MIROC6 when a prognostic precipitation scheme is introduced
Cloud altitude feedback is associated with high clouds in the present climate, which is better represented by prognostic precipitation
Cloud altitude feedback in CMIP models is suggested to increase when their underestimation of high‐level clouds is mitigated
To examine the influence of season and climate (air temperature and humidity) on water intake by the food group in a sample of free-living Japanese adults.
Four-nonconsecutive-day, semi-weighed ...dietary records were collected from each of the four seasons in a single 12-month period (16 days in total). The influence of season and climate on individual water intake by the food group was analyzed using a mixed linear model. Participants were 242 healthy adults (121 women aged 30-69 years and 121 men aged 30-76 years) from four areas in Japan.
For women and men together, the mean total water intake was 2230 g/day (highest in summer: 2331 g/day; lowest in winter: 2134 g/day). Fifty-one percent of water was derived from foods and the rest from beverages. In a mixed linear model adjusted for sex, age and body mass index, intake of water from foods decreased by 3.1 g/day and that from beverages increased by 8.4 g/day, with an increase in the mean outdoor air temperature on the survey day of 1 °C (both P < 0.0001). The influence of humidity was nonsignificant.
In contrast to previous findings in Western countries, half of water intake in Japanese adults was derived from foods. Water intake from beverages was positively associated with air temperature, whereas that from foods was inversely associated with air temperature.
Abstract
Cloud feedback remains the largest source of uncertainty in equilibrium climate sensitivity (ECS). Many studies have attempted to narrow uncertainties in cloud feedback and ECS by proposing ...observable metrics with high skill at predicting future climate, referred to as emergent constraints. These constraints are often associated with clouds, convection, and circulation, and are interrelated. However, physical explanations for these connections remain unclear. Here, we propose a new mechanism relating convection and clouds across multiple climate models. Some models show overly active deep convection on daily timescales in the subtropical low cloud regions, which contributes to weaker subsidence inversion and smaller amounts of low-level clouds. Such models predict smaller shortwave (SW) cloud feedback. Using precipitation frequency in these regions as an emergent constraint, encapsulating this mechanism, models with lower SW cloud feedback (<0.50 W m
−2
°C
−1
) are found to exhibit erroneously frequent convection. Our results suggest that further improvements in understanding and better modeling of cloud and convective systems are necessary for accurate climate predictions.
In this study, the tunable properties of a bio-lens from a deep-sea shrimp were investigated for the first time using magnetic fields. The skin of the shrimp exhibited a brilliantly colored ...reflection of incident white light. The light reflecting parts and the oil droplets in the shrimp’s skin were observed in a glass slide sample cell using a digital microscope that operated in the bore of two superconducting magnets (maximum strengths of 5 and 13 T). In the ventral skin of the shrimp, which contained many oil droplets, some comparatively large oil droplets (50 to 150 μm in diameter) were present. A distinct response to magnetic fields was found in these large oil droplets. Further, the application of the magnetic fields to the sample cell caused a change in the size of the oil droplets. The phenomena observed in this work indicate that the oil droplets of deep sea shrimp can act as lenses in which the optical focusing can be modified via the application of external magnetic fields. The results of this study will make it possible to fabricate bio-inspired soft optical devices in future.
A mode-locked and Q-switched short pulse laser using the Nd3+/Cr3+:YAG ceramic has been constructed with a SESAM and Cr4+:YAG crystal optical switch based on excite state absorption (ESA). Laser ...oscillations of the pulse laser were observed experimentally. The Nd/Cr:YAG ceramic laser has a high conversion efficiency from white light (such as lamp light or solar light) to the laser. The Nd/Cr:YAG ceramic has a higher laser gain than the Nd:YAG laser for the same pumping power. The laser oscillation can be obtained very easily. A single-mode-locked laser pulse with fast modulation on the order of 100 ps was obtained in some pump power regimes when using the Cr4+:YAG crystal. The obtained pulse duration of the short pulse was a few hundred ps. A maximum peak power of 60 kW was obtained when using a SESAM. The same level of peak power (60 kW) was also obtained when using the Cr4+:YAG crystal.
One of the reasons of the deterioration of the power generation efficiency of the thermal power generation is the adhesion of the iron scale generated by the corrosion of the pipe to the inner wall ...of the feed-water system. Focusing on the magnetic property of scale, we studied on the removal of scales in the feed-water system by high gradient magnetic separation (HGMS) using the superconducting magnet. In this study, we targeted the thermal power plants adopting oxygenated treatment (OT). In order to determine the installation site and the magnetic separation condition of the HGMS system, we analyzed the OT scale and then clarified the aggregation/composite states by magnetic separation experiment. It is concluded that low-pressure feed-water heater drain is suitable for installation site of HGMS system. In addition, it was clarified that homogeneous aggregation particles existed in the OT scale.
Tilapia fish-scale type I atelocollagen hydrogels with aligned fibril structures were fabricated under a strong magnetic field of 6 or 12 T using two different methods. In the first method, a ...solution of acid-soluble collagen was neutralized with phosphate buffer saline and maintained in the magnetic field at 28
°C for 3
h. Under these conditions fibrogenesis occurs, and a hydrogel is formed. The hydrogel was subsequently crosslinked with ethyl-dimethylcarbodiimide (EDC). In the second method, the hydrogels were formed as described above, but in the absence of an applied magnetic field. Only after being crosslinked with EDC were these gels exposed to the magnetic field (28
°C for 3
h). Both methods led to alignment of the collagen fibrils perpendicular to the magnetic direction, the extent of which depended on the duration of magnetic treatment. Even after EDC treatment, collagen fibrils can align, indicating that crosslinking has taken place within fibrils. Both sorts of aligned hydrogels exhibited similar rheological properties with higher storage and loss moduli than were observed with unoriented gels. The hydrogels treated at 6 T had the best rheological properties. The decrease in tangent angle phase delta indicated that the ratio of elasticity to viscosity was greater in the crosslinked than in the non-crosslinked hydrogels. Atomic force microscopy images showed that magnetic treatment had no effect on the nanostructure of collagen fibrils. Differential scanning calorimetry measurements indicated that collagen hydrogels with and without magnetic treatment had the same denaturation temperature, 48
°C, while EDC crosslinking increased the denaturation temperature to 62
°C.
Abstract
The westerly phase of the quasi-biennial oscillation (QBO) was unexpectedly disrupted by an anomalous easterly near 40 hPa (~23 km) in February 2016. At the same time, a very strong El Nino ...and a very low Arctic sea-ice concentration in the Barents and Kara Sea were present. Previous studies have shown that the disruption of the QBO was primarily caused by the momentum transport of the atmospheric waves in the Northern Hemisphere. Our results indicate that the tropical waves evident over the Atlantic, Africa, and the western Pacific were associated with extratropical disturbances. Moreover, we suggest that the El Nino and sea-ice anomalies in 2016 account for approximately half of the disturbances and waves based on multiple regression analysis of the observational/reanalysis data and large-ensemble experiments using an atmospheric global climate model.
Background: We cultured Dermatophagoides farinae (Df), one of the most common mites in house dust and the most important allergen among natural allergens. With this material, we attempted to produce ...an animal model of the atopic eczema/dermatitis syndrome (AEDS).
Methods: We cultured Df mites in high density and prepared a crude extract of Df (DfE) together with the culture medium. We applied the extract to the back skin of NC/Nga and BALB/c mice three times per week for 8 weeks.
Results: In the NC/Nga group, dryness or scaling appeared on the skin, and scratching behavior increased at the second week in the DfE‐treated group. Skin erosion and hemorrhage occurred at the fourth week. The epidermis thickened and deepened into the upper dermis, in which mast cells were highly accumulated, corresponding with the skin lesion of AEDS patients. Specific IgE and IgG to DfE and total IgE were elevated in the sera. Mice treated with an extract of mite culture medium did not develop skin lesions. In the BALB/c group, mice developed specific IgE and IgG to DfE, however, no typical skin lesions appeared. Mast cells in the upper dermis did not increase.
Conclusions: Repeated painting of Dermatophagoides extract produced IgE‐associated AEDS‐like lesions on the skin of NC mice.
The large increase in the springtime free tropospheric ozone over the western and eastern North Pacific over the last decades has been linked to the increase in anthropogenic emissions in China. ...However, the increasing trend at Mt. Happo, Japan, has been unexpectedly suppressed since 2008, by 5–10 ppbv. In this paper, we analyzed the tropospheric ozone records at Mt. Happo, along with the changes in climate and anthropogenic emissions. We revealed, based only on observational data, that the changes in climate pattern play an important role in controlling the decadal ozone trend. We found that the persistent La Niña‐like wind pattern during 2008–2013 reduced the export of polluted air masses from East Asia to the western Pacific, even though Chinese emissions continued to increase. On the other hand, an El Niño‐like wind pattern during 1992–1996 and enhanced storm track activity during 2000–2006 enhanced the export of polluted air masses from East Asia, contributing to the accelerated ozone trends. The climate modulations were identified in the O3 trends at the surface sites in western and central Japan and at a remote marine boundary layer site, Minamitorishima. Without this climatic effect driven by the persistent La Niña‐like wind pattern, the ozone trend would have been further upward over the North Pacific in the late 2000s to the early 2010s.
Key Points
Tropospheric ozone level at Mt. Happo, Japan, dropped in the late 2000s, despite increasing Chinese emissions
Persistent La Niña‐like wind pattern has reduced long‐range transport from East Asia via weakened westerly winds
Without the persistent La Niña‐like wind pattern, the ozone trend over Japan would have been further upward in the late 2000s
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