Search

Projected changes in extreme climate are occasionally predicted through multi-model ensemble methods using a weighted averaging that combines predictions from individual simulation models. To predi...

Projections of changes in extreme climate are sometimes predicted by multimodel ensemble methods that combine forecasts from individual simulation models using weighted averaging. One method to assign weight to each model is the Bayesian model averaging (BMA) in which posterior probability is used. For the cases of extreme climate, the generalized extreme value distribution (GEVD) is typically used. We applied the approach of GEV‐embedded BMA to a series of 35 years of the annual maximum daily precipitation data (both historical data and data gathered from simulation experiments for future periods) over the Korean peninsula as simulated by the models in the Coupled Model Intercomparison Project Phase 5 (CMIP5). Simulation data under two Representative Concentration Pathway (RCP) scenarios, namely RCP4.5 and RCP8.5, were used. Observed data and 17 CMIP5 models for 12 gird cells in Korea have been examined to predict future changes in precipitation extremes. A simple regional frequency analysis of pooling observations from three stations in each cell was employed to reduce the estimation variance and local fluctuations. A bias correction technique using the regression‐type transfer function was applied to these simulation data. Return levels spanning over 20 and 50 years, as well as the return periods relative to the reference years (1971–2005), were estimated for two future periods, namely Period 1 (2021–2050) and Period 2 (2066–2095). From these analyses, relative increase observed in the spatially averaged 20‐year (50‐year) return level was approximately 23% (16%) and 45% (36%) in the RCP4.5 and RCP8.5 experiments, respectively, by the end of the 21st century. We concluded that extreme rainfalls will likely occur two times and four times more frequently in the RCP4.5 and RCP8.5 scenarios, respectively, as compared to in the reference years by the end of the 21st century.

A highly coordinated complex known as the microprocessor precisely processes primary transcripts of MIRNA genes into mature miRNAs. In plants, the microprocessor minimally consists of three components: Dicer-like protein 1 (DCL1), HYPONASTIC LEAF 1 (HYL1), and SERRATE (SE). To precisely modulate miRNA maturation, the microprocessor cooperates with at least 12 proteins in plants. In addition, we here show the involvement of a novel gene, HYL1-interacting GIY-YIG-like endonuclease (HIGLE). The encoded protein has a GIY-YIG domain that is generally found within a class of homing endonucleases. HIGLE directly interacts with the microprocessor components HYL1 and SE. Unlike the functions of other GIY-YIG endonucleases, the catalytic core of HIGLE has both DNase and RNase activities that sufficiently processes miRNA precursors into short fragments in vitro.

In this study, spatial and temporal patterns of changes in extreme events of temperature and precipitation at 143 weather stations in ten Asia-Pacific Network (APN) countries and their associations with changes in climate means are examined for the 1955–2007 period. Averaged over the APN region, annual frequency of cool nights (days) has decreased by 6.4 days/decade (3.3 days/decade), whereas the frequency of warm nights (days) has increased by 5.4 days/decade (3.9 days/decade). The change rates in the annual frequency of warm nights (days) over the last 20 years (1988–2007) have exceeded those over the full 1955–2007 period by a factor of 1.8 (3.4). Seasonally, the frequencies of summer warm nights and days are changing more rapidly per unit change in mean temperatures than the corresponding frequencies for cool nights and days. However, normalization of the extreme and mean series shows that the rate of changes in extreme temperature events are generally less than that of mean temperatures, except for winter cold nights which are changing as rapidly as the winter mean minimum temperature. These results indicate that there have been seasonally and diurnally asymmetric changes in extreme temperature events relative to recent increases in temperature means in the APN region. There are no systematic, regional trends over the study period in total precipitation, or in the frequency and duration of extreme precipitation events. Statistically significant trends in extreme precipitation events are observed at fewer than 30% of all weather stations, with no spatially coherent pattern of change, whereas statistically significant changes in extreme temperature events have occurred at more than 70% of all weather stations, forming strongly coherent spatial patterns. Copyright © 2009 Royal Meteorological Society

Winter surface air temperature in East Asia is negatively correlated with a wave pattern over the Eurasian continent, called the Eurasian pattern (EU). While previous studies have reported a correlation between the EU and East Asian winter temperature on a monthly mean time scale, this study focuses on the daily scale. To this end, a new definition of the EU index (EUw) was suggested, and daily lag composite maps were constructed with respect to positive and negative peaks of the daily EUw values. Three days after the peak, an apparent temperature fall/rise appears, accompanied by strong wind advection over East Asia. An analysis of the probabilities of cold and warm weather events also shows strong dependence on the EU phase. Copyright © 2008 Royal Meteorological Society

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae), is a worldwide pest of cruciferous crops. We examined the female pheromone production and male response to various pheromone blends in two Korean populations. Gas chromatography (GC) and GC-mass spectrometry (MS) analyses of pheromone gland extracts revealed that females produce (Z)-11-hexadecenal (Z11-16:Ald), (7)-11-hexadecenyl acetate (Z11-16:OAc), and (Z)-11-hexadecen-1-ol (Z11-16:OH) in a ratio of 8:100:18. However, (Z)-9-tetradecenyl acetate (Z9-14:OAc), a previously reported component of the sex attractant of a Canadian P. xylostella population was not detected in gland extracts of the Korean one. Field tests showed that Z11-16:Ald and Z11-16:OAc are essential for attraction of male moths, and the highest attraction is obtained with a 10:90 blend mimicking the blend found in gland extracts. Addition of 1 or 10% of Z11-16:OH to the 10:90 blend of Z11-16:Ald and Z11-16:OAc significantly increased attraction. However, attraction was strongly antagonized by the addition of as little as 0.1% of Z9-14:OAc to the most attractive ternary blend. The ternary blend of Z11-16:Ald, Z11-16:OAc, and Z11-16:OH at a ratio of 10:90:1 was more effective at catching P. xylostella males than the Japanese three-component blend or the Canadian four-component blend in Korea. These results suggest that there is geographical variation in the pheromone systems of this species.

The mechanisms and strategies for winter survival of the black rice bug Scotinophara lurida are investigated along with the relationship between cold hardiness and diapause. The ability of S. lurida to survive subzero temperatures varies depending on developmental stage, temperature and exposure duration. Mean supercooling point (SCP) varies from –7.6 to –10.7 °C with developmental stage, but is not significantly different between stages examined. The SCP also varies with season, being lowest in January and increasing rapidly in February and remaining almost at the same level (–7.3 to 9.6 °C) until April The osmolality of haemolymph of field-collected S. lurida adults rises dramatically from 53.9 mOsm kg−1 in August to 75.3 mOsm kg−1 in December, and then declines linearly to 57.0 mOsm kg−1 in May. Field-collected S. lurida adults show a peak glucose content in October, glycerol content in November and trehalose content in December. Only trehalose content decreases after the application of the juvenile hormone analogue, fenoxycarb, suggesting that trehalose is a cryoprotectant during diapause. These various physiological and biochemical traits related to cold tolerance in S. lurida may be, at least in part, under the control of juvenile hormone through the reproductive diapause programme.