Effect of Ocean Thermal Diffusivity on Global Warming Induced by Increasing Atmospheric CO_2

A global mean ocean model including atmospheric heating, heat capacity of the mixed layer ocean, and vertical thermal diffusivity in the lower ocean, proposed by Cess and Goldenberg (1981), is used in this paper to study the sensitivity of global warming to the vertical diffusivity. The results suggest that the behaviour of upper ocean temperature is mainly determined by the magnitude of upper layer diffusivity and an ocean with a larger diffusivity leads to a less increase of sea surface temperature and a longer time delay for the global warming induced by increasing CO2 than that with smaller one. The global warming relative to four scenarios of CO2 emission assumed by Intergovernmental Panel of Climate Change (IPCC) is also estimated by using the model with two kinds of thermal diffusivities. The result shows that for various combinations of the CO2 emission scenarios and the diffusivities, the oceanic time delay to the global warming varies from 15 years to 70 years.

A numerical study of the impact of SST anomaly in the warm pool area on atmospheric circulation in winter

In this paper the impacts of the anomalous SST in the warm pool area of the Western Equatorial Pacific on the winter time circulation and the East Asian monsoon are studied by using the NCAR CCM. It is found that the abnormal heating in the warm pool area will change the strength and the position of the Walker Cell in the Equatorial Pacific and the anti-Walker Cell in the equatorial Indian Ocean. Both the Walker and anti-Walker Cells are strengthened. The local Hadley Cells over two hemispheres near the warm pool are also strengthened. The subtropical highs in two hemispheres become stronger and move poleward slightly. The westerly jets in the extratropical regions have similar changes as the subtropical highs. The winter monsoon in South-East Asia is weakened by the abnormal heating in the warm pool. The experiment also show that there are wave trains emanating from surrounding areas of the warm pool to the high latitudes, causing various changes in circulations and local weather.

High temperature enhances anthocyanin coloration in Asiatic hybrid lily flowers via upregulation of the MYB12 positive regulator

Although high atmospheric temperatures suppress anthocyanin accumulation in most plant species,we show that high temperatures accelerate anthocyanin pigmentation in flower tepals of Asiatic hybrid lilies(Lilium spp.).After incubation at high temperatures(35℃)for two days,anthocyanin color became deeper in the most of tepal parts of two Asiatic hybrid lily cultivars,although the basal parts of’Montreux’tepals and top parts of’Toronto’outer tepals were whitened.Environmental stimuli often affect the expression of R2R3-MYB positive regulators that control anthocyanin biosynthesis.Although their expression is often suppressed by hot temperatures in other species,the expression of lily MYB12 in tepals was upregulated by high temperatures.MicroRNA828(miR828),which suppresses the action of MYB12 post-transcriptionally,exhibited reduced accumulation levels under high temperature,indicating that miR828 regulation is involved in MYB12 upregulation.In addition,transcription levels of MYB12,estimated by unspliced MYB12 transcript accumulation,were also activated by high temperatures.Thus,both suppressed miR828 accumulation and increased MYB12 transcription are likely to be involved in MYB12 activation at high temperatures.In the whitened basal parts of’Montreux’tepals at 35℃,expression of bHLH2 was severely suppressed while that of MYB12 was not affected.The present results demonstrate that plants display diverse responses to hot climatic conditions and shed new light on anthocyanin regulation under various environmental conditions.