Abstract. The European Centre for Medium-Range Weather Forecasts' (ECMWF's) next-generation reanalysis ERA5 provides many improvements, but it also confronts the community with a “big data” challenge. Data storage requirements for ERA5 increase by a factor of ∼80 compared with the ERA-Interim reanalysis, introduced a decade ago. Considering the significant increase in resources required for working with the new ERA5 data set, it is important to assess its impact on Lagrangian transport simulations. To quantify the differences between transport simulations using ERA5 and ERA-Interim data, we analyzed comprehensive global sets of 10-day forward trajectories for the free troposphere and the stratosphere for the year 2017. The new ERA5 data have a considerable impact on the simulations. Spatial transport deviations between ERA5 and ERA-Interim trajectories are up to an order of magnitude larger than those caused by parameterized diffusion and subgrid-scale wind fluctuations after 1 day and still up to a factor of 2–3 larger after 10 days. Depending on the height range, the spatial differences between the trajectories map into deviations as large as 3 K in temperature, 30 % in specific humidity, 1.8 % in potential temperature, and 50 % in potential vorticity after 1 day. Part of the differences between ERA5 and ERA-Interim is attributed to the better spatial and temporal resolution of the ERA5 reanalysis, which allows for a better representation of convective updrafts, gravity waves, tropical cyclones, and other meso- to synoptic-scale features of the atmosphere. Another important finding is that ERA5 trajectories exhibit significantly improved conservation of potential temperature in the stratosphere, pointing to an improved consistency of ECMWF's forecast model and observations that leads to smaller data assimilation increments. We conducted a number of downsampling experiments with the ERA5 data, in which we reduced the numbers of meteorological time steps, vertical levels, and horizontal grid points. Significant differences remain present in the transport simulations, if we downsample the ERA5 data to a resolution similar to ERA-Interim. This points to substantial changes of the forecast model, observations, and assimilation system of ERA5 in addition to improved resolution. A comparison of two Lagrangian trajectory models allowed us to assess the readiness of the codes and workflows to handle the comprehensive ERA5 data and to demonstrate the consistency of the simulation results. Our results will help to guide future Lagrangian transport studies attempting to navigate the increased computational complexity and leverage the considerable benefits and improvements of ECMWF's new ERA5 data set.

In this work, we investigated in detail the structural characteristics of mixtures of choline chloride and urea with different urea contents by performing molecular dynamic (MD) simulations, and offer possible explanations for the low melting point of the eutectic mixture of choline chloride and urea with a ratio of 1:2. The insertion of urea molecules was found to change the density distribution of cations and anions around the given cations significantly, disrupting the long-range ordered structure of choline chloride. Moreover, with increasing urea concentration, the hydrogen bond interactions between choline cations and Cl − anions decreased, while those among urea molecules obviously increased. From the hydrogen bond lifetimes, it was found that a ratio of 1:2 between choline chloride and urea is necessary for a reasonable strength of hydrogen bond interaction to maintain the low melting point of the mixture of choline chloride with urea. In addition, it was also deduced from the interaction energies that a urea content of 67.7 % may make the interactions of cation-anion, cation-urea and anion-urea modest, and thus results in the lower melting point of the eutectic mixture of choline chloride and urea. The present results may offer assistance to some extent for understanding the physicochemical properties of the eutectic mixture of choline chloride and urea, and give valuable information for the further development and application of deep eutectic solvents.

Enhancer II (ENII) of hepatitis B virus (HBV) is one of the essential cis-elements for the transcriptional regulation of HBV gene expression. Its function is highly liver-specific, suggesting that liver-enriched transcriptional factors play critical roles in regulating the activity of ENII. In this report, a novel hepatocyte transcription factor, which binds specifically to the B1 region (AACGACCGACCTTGAG) within the major functional unit (B unit) of ENII, has been cloned from a human liver cDNA library by yeast one-hybrid screening, and demonstrated to trans-activate ENII via the B1 region. We named this factor hB1F, for human B1-binding factor. Amino acid analysis revealed this factor structurally belongs to nuclear receptor superfamily. Based on the sequence similarities, hB1F is characterized to be a novel human homolog of the orphan receptor fushi tarazu factor I (FTZ-F1). Using reverse transcriptionpolymerase chain reaction, a splicing isoform of hB1F (hB1F-2) was identified, which has an extra 46 amino acid residues in the A/B region. Examination of the tissue distribution has revealed an abundant 5.2-kilobase transcript of hB1F is present specifically in human pancreas and liver. Interestingly, an additional transcript of 3.8 kilobases was found to be present in hepatoma cells HepG2. Fluorescent in situ hybridization has mapped the gene locus of hB1F to the region q31-32.1 of human chromosome 1. Altogether, this study provides the first report that a novel human homolog of FTZ-F1 binds and regulates ENII of HBV. The potential roles of this FTZ-F1 homolog in tissue-specific gene regulation, in embryonic development, as well as in liver carcinogenesis are discussed. Hepatitis B virus (HBV)1 is the major cause of acute and chronic hepatitis, also closely associated with the development of hepatocellular carcinoma (1). HBV predominantly infects hepatocytes, which is a prominent characteristic of hepadnaviruses. The genome of HBV is a small, circular, partially doublestranded DNA of about 3.2 kb, which contains four partially overlapping open reading frames (ORF) encoding the surface antigens (preS/S), the core antigen/e antigen (preC/C), the polymerase (P) and the X protein (X), respectively (2, 3). These HBV genes express specifically in liver, controlled by the combinatorial action of the promoters and enhancers. To date, four promoters (Sp1, Sp2, Cp, and Xp) (4) have been identified to be responsible for the transcription of the viral mRNAs, and they are regulated by two HBV enhancers. Enhancer I (ENI) functions in a relatively tissue independent manner (5, 6), while enhancer II (ENII) shows strong hepatocyte specificity. Enhancer II of HBV is located within the X ORF, about 600 bp downstream of ENI (7-9). In our previous study, ENII was mapped in a 148-bp region from nt 1627 to 1774 (HBV adr1 subtype), partially overlapped with the core promoter (Cp) (7). According to the functional analyses, it can be divided into two parts, A and B, with part B as the basal functional unit, which could be further subdi...

Forecasting the intensity of tropical cyclones is a challenging problem. Rapid intensification is often preceded by the formation of “hot towers” near the eyewall. Driven by strong release of latent heat, hot towers are high‐reaching tropical cumulonimbus clouds that penetrate the tropopause. Hot towers are a potentially important source of stratospheric gravity waves. Using 13.5 years (2002–2016) of Atmospheric Infrared Sounder observations of stratospheric gravity waves and tropical cyclone data from the International Best Track Archive for Climate Stewardship, we found empirical evidence that stratospheric gravity wave activity is associated with the intensification of tropical cyclones. The Atmospheric Infrared Sounder and International Best Track Archive for Climate Stewardship data showed that strong gravity wave events occurred about twice as often for tropical cyclone intensification compared to storm weakening. Observations of stratospheric gravity waves, which are not affected by obscuring tropospheric clouds, may become an important future indicator of storm intensification.