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[1] The effects of aerosols on the development and precipitation for a mesoscale squall line occurring in the south plains of the United States have been investigated using a cloud-resolving Weather Research and Forecasting (CR-WRF) model with a two-moment bulk microphysical scheme. Different aerosol scenarios are considered in the CR-WRF model experiments, including polluted continental aerosols with a mean concentration of 2000 cm À3 . The simulated temporal evolution of composite radar reflectivity and the 24-h accumulated precipitation in the polluted aerosol experiment are in agreement with the measurements. The influence of aerosol concentrations is insignificant on the rainfall distribution but is remarkable on the precipitation intensity. The CR-WRF experiment with the polluted aerosol case predicts about 13% more precipitation and more locally intensive rainfall than do those with the clean aerosol case. Both the convection zone and the storm convective strength are increased in the polluted aerosol experiment in response to the increase in aerosol concentrations. The two-moment microphysical scheme is compared with three single-moment bulk schemes in the WRF model, including the Lin, WRF single-moment six-class, and Thompson schemes. Only the Thompson schemes reproduce the observed precipitation and radar reflectivity pattern, in agreement with the twomoment scheme with a leading convective line and a trailing stratiform precipitation regime. All of the single-moment schemes significantly overestimate the precipitation, especially with the Lin scheme, while the two-moment scheme yields the precipitation simulation comparable with the measurement.

[1] An analysis of the results from the Global Precipitation Climatology Project (GPCP) reveals a trend of increased wintertime precipitation over the North Pacific from 1984 to 2005. The precipitation over the North Pacific increases by about 1.5 mm/year in winter during the period of 1984 to 2005. Statistic analyses are performed to validate the observed precipitation trend, showing the f-test and t-test significances of greater than 99%. A cloud-resolving weather research and forecast (CR-WRF) model with a two-moment bulk microphysical scheme is employed to consider the effects of an increasing Asian pollution outflow on wintertime precipitation over the North Pacific. The CR-WRF simulations demonstrate more precipitation with elevated polluted continental aerosols than that with typical maritime aerosols, reproducing the observed precipitation trend. The results suggest that the increasing Asian pollution outflow represents one of the most plausible explanations for the increased precipitation trend observed in winter over the North Pacific, likely with important climate implications. Citation:

Anal fissure is a common anorectal condition, yet its pathogenesis remains unclear. Lateral internal sphincterotomy (LIS) is the gold standard treatment for chronic anal fissures that do not respond to conservative treatment; however, it has a risk of anal incontinence. We believe that fibrosis of the internal anal sphincter is an important factor in the pathogenesis of chronic anal fissure. In this study, we describe the minimal LIS method, a minimally invasive method where only the fibrotic portion of the internal anal sphincter is cut. We also describe the outcomes of this method. Methods: We performed a retrospective review of 468 patients (270 male and 198 female) who underwent minimal LIS for chronic anal fissure in 2017 at Seoul Song Do Hospital. We analyzed the patients' clinical characteristics, manometry data, complications, and outcomes of minimal LIS. The outcomes of the surgery were assessed via questionnaires during the postoperative outpatient visits, beginning 2 weeks postoperatively. Results: The overall complication rate was 4.0% (19 patients). Delayed healing occurred in 14 patients (3.0%), perianal abscess was present in 3 patients (0.6%), and gas incontinence occurred in 2 patients (0.4%). All complications were improved with conservative treatment. Recurrence, defined as the recurrence of anal fissure more than 4 weeks after healing, was present in 6 patients (1.3%). Conclusion: Minimal LIS is a safe and effective treatment option for patients with chronic anal fissure. Postoperative complications, especially incontinence and recurrence, are rare.