CMIP5 model simulations of the Pacific meridional mode and its connection to the two types of ENSO

© 2014 Royal Meteorological Society. This study examines the Pacific meridional mode (PMM) simulated in the pre-industrial simulations of the Coupled Model Intercomparison Project Phase 5 (CMIP5). The spatial pattern and intensity of the PMM were found to be reasonably simulated by CMIP5 models, as was the subtropical atmosphere-ocean coupling associated with the PMM. However, the persistence of the coupling, which sustains the PMM's duration and extends its pattern equatorward, was found to be underestimated in most of the CMIP5 models. Many of the simulated PMMs do not have a pattern that extends far enough into the tropical Pacific to influence El Niño-Southern Oscillation (ENSO). The CMIP5 models that do produce longer persistence for the PMM coupling show a higher correlation of the PMM with the Central-Pacific (CP) type of ENSO than with the Eastern-Pacific (EP) type of the ENSO. This study concludes that (1) the PMM and its associated subtropical Pacific ocean-atmosphere coupling are important to the generation of the CP type of ENSO; (2) the so-called seasonal footprinting mechanism that sustains an equatorward extension of the PMM is not well simulated in a majority of the CMIP5 models; and (3) the persistence of the subtropical Pacific coupling is more important than the other properties in gauging a model's skill in the PMM simulation

The relationship between El Niño and the western North Pacific summer climate in a coupled GCM: role of the transition of El Niño decaying phases

This study investigates the impacts of the transition of El Niño decaying phases on the western North Pacific anticyclone (WNPAC) anomalies in the subsequent summer with a coupled GCM. The modeling results suggest that the El Niños with short decaying phases lead to significant WNPAC anomalies in the following summer, which are contributed to mainly by the El Niños followed by La Niñas, in comparison with those not followed by La Niñas. In contrast, the long decaying cases are associated with the disappearance of WNPAC anomalies in the summer. These differences in the WNP circulation anomalies can be explained by the different configurations of simultaneous SSTs in the Indian Ocean and in the central and eastern tropical Pacific: positive SSTs in the former region and negative ones in the latter region constructively induce significant WNPAC anomalies for the short decaying cases, while the roles of positive SSTs in both regions for the long decaying cases work destructively and lead to weak WNP circulation anomalies. Further analysis indicates that the different lengths of El Niño decaying phases are predicted by the strength of Indian Ocean SSTs in the mature winter. The warmer wintertime Indian Ocean SSTs favor the anomalous easterly wind over the western and central equatorial Pacific in the subsequent summer, leading to a short decaying of El Niño. Thus, the strength of wintertime Indian Ocean SSTs is one of the important factors that affect the length of El Niño decaying phase and resultant WNPAC anomalies in the following summer

Whole-genome, transcriptome, and methylome analyses provide insights into the evolution of platycoside biosynthesis in Platycodon grandiflorus, a medicinal plant

Triterpenoid saponins (TSs) are common plant defense phytochemicals with potential pharmaceutical properties. Platycodon grandiflorus (Campanulaceae) has been traditionally used to treat bronchitis and asthma in East Asia. The oleanane-type TSs, platycosides, are a major component of the P. grandiflorus root extract. Recent studies show that platycosides exhibit anti-inflammatory, antiobesity, anticancer, antiviral, and antiallergy properties. However, the evolutionary history of platycoside biosynthesis genes remains unknown. In this study, we sequenced the genome of P. grandiflorus and investigated the genes involved in platycoside biosynthesis. The draft genome of P. grandiflorus is 680.1Mb long and contains 40,017 protein-coding genes. Genomic analysis revealed that the CYP716 family genes play a major role in platycoside oxidation. The CYP716 gene family of P. grandiflorus was much larger than that of other Asterid species. Orthologous gene annotation also revealed the expansion of beta -amyrin synthases (bASs) in P. grandiflorus, which was confirmed by tissue-specific gene expression. In these expanded gene families, we identified key genes showing preferential expression in roots and association with platycoside biosynthesis. In addition, whole-genome bisulfite sequencing showed that CYP716 and bAS genes are hypomethylated in P. grandiflorus, suggesting that epigenetic modification of these two gene families affects platycoside biosynthesis. Thus whole-genome, transcriptome, and methylome data of P. grandiflorus provide novel insights into the regulation of platycoside biosynthesis by CYP716 and bAS gene families

Evaluating ENSO teleconnections using observations and CMIP5 models

Bias correction of global and regional climate models is essential for credible climate change projections. This study examines the bias of the models of the Coupled Model Inter-comparison Project Phase 5 (CMIP5) in their simulation of the spatial pattern of sea surface temperature (SSTs) in different phases of the El Niño Southern Oscillation (ENSO) and their teleconnections—highlighting the strengths and weaknesses of the models in different oceanic sectors. The comparison between the model outputs and the observations focused on the following three features: (i) the typical horseshoe pattern seen in the Pacific Ocean during ENSO events with anomalies in SSTs opposite to the warm/cool tongue, (ii) different signature in the tropical Pacific Ocean from that of the North and tropical Atlantic Ocean, and (iii) spurious signature in the southern hemisphere beyond 45° S. Using these three cases, it was found that the model simulations poorly matched the observations, indicating that more attention is needed on the tropical/extratropical teleconnections associated with ENSO. More importantly, the observed SST coupling between the tropical Pacific Ocean and the Atlantic Ocean is missing in almost all models, and differentiating the models between high/low top did not improve the results. It also found that SSTs in the tropical Pacific Ocean are relatively well simulated when compared with observation. This work has improved our understanding of the simulation of ENSO and its teleconnections in the CMIP5 models and has raised awareness of the bias existing in the models, which requires further attention by climate modellers. © 2018 The Author(s

The multipartite mitochondrial genome of Cynanchum auriculatum (Gentianales: Apocynaceae)

Cynanchum auriculatum is a Chinese herbal medicine species in the family Apocynaceae. The mitochondrial genome of C. auriculatum has heteroplasmy and consists of two chromosomes (chromosomes I and II), the lengths of which are 614,836 and 426,495 nucleotides. The multipartite mitochondrial genome encodes 57 genes, including 37 protein-coding genes, 17 transfer RNA genes, and three ribosomal RNA genes. Including 44 overlapping genes, we identified 57 genes on chromosome I and 44 genes on chromosome II. A phylogenetic tree revealed that C. auriculatum is most closely related to Asclepias syriaca

The complete chloroplast genome of Cirsium japonicum (Asterales: Asteraceae)

Cirsium japonicum (C. japonicum) is an important oriental herb belonging to the family Asteraceae. The C. japonicum complete chloroplast genome is composed of 152,606 bp, which form a large single-copy region (LSC, 83,492 bp), a small single-copy region (SSC, 18,772 bp), and 2 inverted repeats (IRs, 25,196 bp). There are 114 genes annotated, including 80 protein-coding genes, 4 ribosomal RNA genes, and 30 transfer RNA genes. Our phylogenetic analysis suggests that C. japonicum is closely related to the Cirsium genus of the Asteraceae family, and that C. japonicum (subfamily: Carduoideae) is separate from the Asteroideae subfamily