Evaluation of the Global and Regional Assimilation and Prediction System for Predicting Sea Fog over the South China Sea

In the South China Sea, sea fog brings severe disasters every year, but forecasters have yet to implement an effective seafog forecast. To address this issue, we test a liquid-water-content-only(LWC-only) operational sea-fog prediction method based on a regional mesoscale numerical model with a horizontal resolution of about 3 km, the Global and Regional Assimilation and Prediction System(GRAPES), hereafter GRAPES-3 km. GRAPES-3 km models the LWC over the sea, from which we infer the visibility that is then used to identify fog. We test the GRAPES-3 km here against measurements in 2016 and 2017 from coastal-station observations, as well as from buoy data, data from the Integrated Observation Platform for Marine Meteorology, and retrieved fog and cloud patterns from Himawari-8 satellite data. For two cases that we examine in detail, the forecast region of sea fog overlaps well with the multi-observational data within 72 h. Considering forecasting for0–24 h, GRAPES-3 km has a 2-year-average equitable threat score(ETS) of 0.20 and a Heidke skill score(HSS) of 0.335,which is about 5.6%(ETS) and 6.4%(HSS) better than our previous method(GRAPES-MOS). Moreover, the stations near the particularly foggy region around the Leizhou Peninsula have relatively high forecast scores compared to other sea areas.Overall, the results show that GRAPES-3 km can roughly predict the formation, evolution, and dissipation of sea fog on the southern China coast.

Ensemble Based Diagnosis of the Track Errors of Super Typhoon Mangkhut(2018)

Super Typhoon Mangkhut(2018)was the most high-impact typhoon in 2018 because of its long lifespan and significant intensity.The operational track forecasts in the short-to-medium range(deterministic and probabilistic forecast)showed a great uncertainty and the forecast landing points varied with different lead times.This study applied ensembles of high-resolution ECMWF forecasts to investigate the major factors and mechanisms of the bias production of the Mangkhut forecast track.The ensembles with the largest track bias were analyzed to examine the possible bias associated factors.The results suggested that environmental steering flows were the main cause for the erroneous southward track error with a variance contribution of 72%.The tropical cyclone(TC)size difference and the interaction of the TC with the subtropical high(SH)were other two key factors that contributed to the track error.Particularly,larger TCs may have led to a stronger erosion of the southern part of the SH,and thus induced significant changes in the large-scale environment and eventually resulted in an additional northward movement of TC.

Micheliolide exerts effects in myeloproliferative neoplasms through inhibiting STAT3/5 phosphorylation via covalent binding to STAT3/5 proteins

Ruxolitinib is a cornerstone of management for some subsets of myeloproliferative neoplasms(MPNs);however,a considerable number of patients respond suboptimally.Here,we evaluated the efficacy of micheliolide(MCL),a natural guaianolide sesquiterpene lactone,alone or in combination with ruxolitinib in samples from patients with MPNs,JAK2V617F-mutated MPN cell lines,and a Jak2V617F knock-in mouse model.MCL effectively suppressed colony formation of hematopoietic progenitors in samples from patients with MPNs and inhibited cell growth and survival of MPN cell lines in vitro.Co-treatment with MCL and ruxolitinib resulted in greater inhibitory effects compared with treatment with ruxolitinib alone.Moreover,dimethylaminomicheliolide(DMAMCL),an orally available derivative of MCL,significantly increased the efficacy of ruxolitinib in reducing splenomegaly and cytokine production in Jak2V617F knock-in mice without evident effects on normal hematopoiesis.Importantly,MCL could target the Jak2V617F clone and reduce mutant allele burden in vivo.Mechanistically,MCL can form a stable covalent bond with cysteine residues of STAT3/5 to suppress their phosphorylation,thus inhibiting JAK/STAT signaling.Overall,these findings suggest that MCL is a promising drug in combination with ruxolitinib in the setting of suboptimal response to ruxolitinib.