@article{glotfelty_alapaty_he_hawbecker_song_zhang_2019, title={The Weather Research and Forecasting Model with Aerosol-Cloud Interactions (WRF-ACI): Development, Evaluation, and Initial Application}, volume={147}, ISSN={["1520-0493"]}, DOI={10.1175/MWR-D-18-0267.1}, abstractNote={Abstract The Weather Research and Forecasting Model with Aerosol–Cloud Interactions (WRF-ACI) is developed for studying aerosol effects on gridscale and subgrid-scale clouds using common aerosol activation and ice nucleation formulations and double-moment cloud microphysics in a scale-aware subgrid-scale parameterization scheme. Comparisons of both the standard WRF and WRF-ACI models’ results for a summer season against satellite and reanalysis estimates show that the WRF-ACI system improves the simulation of cloud liquid and ice water paths. Correlation coefficients for nearly all evaluated parameters are improved, while other variables show slight degradation. Results indicate a strong cloud lifetime effect from current climatological aerosols increasing domain average cloud liquid water path and reducing domain average precipitation as compared to a simulation with aerosols reduced by 90%. Increased cloud-top heights indicate a thermodynamic invigoration effect, but the impact of thermodynamic invigoration on precipitation is overwhelmed by the cloud lifetime effect. A combination of cloud lifetime and cloud albedo effects increases domain average shortwave cloud forcing by ~3.0 W m−2. Subgrid-scale clouds experience a stronger response to aerosol levels, while gridscale clouds are subject to thermodynamic feedbacks because of the design of the WRF modeling framework. The magnitude of aerosol indirect effects is shown to be sensitive to the choice of autoconversion parameterization used in both the gridscale and subgrid-scale cloud microphysics, but spatial patterns remain qualitatively similar. These results indicate that the WRF-ACI model provides the community with a computationally efficient tool for exploring aerosol–cloud interactions.}, number={5}, journal={MONTHLY WEATHER REVIEW}, author={Glotfelty, Timothy and Alapaty, Kiran and He, Jian and Hawbecker, Patrick and Song, Xiaoliang and Zhang, Guang}, year={2019}, month={May}, pages={1491–1511} }
 @article{zhang_hummer_rasdorf_2010, title={Impact of Bead Density on Paint Pavement Marking Retroreflectivity}, volume={136}, ISSN={["1943-5436"]}, DOI={10.1061/(asce)te.1943-5436.0000142}, abstractNote={This paper addresses the impact of bead density on paint pavement marking retroreflectivity. The writers collected retroreflectivity data and glass bead images on 40 segments of two-lane highways. Bead density is defined as the surface percentage of glass beads exposed above the paint marking material. Numerous methods for determining bead density were considered and studied. A new approach, referred to as a computer-aided counting method, was developed and a bead density analysis program was written. The program was used to analyze 108 images to obtain a bead density value for each image. A correlation study was conducted between pavement marking retroreflectivity and bead density. The findings of the study show that the normal range of glass bead density for older markings is 9–24% of the paint marking surface area. Furthermore, bead density values have a positive correlation with marking retroreflectivity readings; higher bead density leads to higher retroreflectivity. White paint markings have significantly higher retroreflectivity values than do yellow markings when the bead density values are the same.}, number={8}, journal={JOURNAL OF TRANSPORTATION ENGINEERING}, author={Zhang, Guanghua and Hummer, Joseph E. and Rasdorf, William}, year={2010}, month={Aug}, pages={773–781} }
 @article{rasdorf_zhang_hummer_2009, title={The Impact of Directionality on Paint Pavement Marking Retroreflectivity}, volume={13}, ISSN={["1552-7549"]}, DOI={10.1177/1087724x08330824}, abstractNote={This article addresses paint centerline pavement marking retroreflectivity. The authors collect yellow centerline retroreflectivity data on two-lane highways, taking measurements in two directions. A paired t test on the data shows that there are differences and they are statistically significant. A field study is initiated to investigate the relationship between the direction the marking is painted and the retroreflectivity direction. The key result of this study is that paint centerline retroreflectivity values measured in the direction of paint striping are significantly higher than values measured in the opposite direction. Findings indicate that it is the lower retroreflectivity values of yellow centerlines (measured in the opposite direction from paint striping) that should be used to compare with the newly proposed Federal Highway Administration minimum standard because the drivers in that direction experience lower marking retroreflectivity at night. The implications for safety, for policy making, and for transportation asset management are significant.}, number={3}, journal={PUBLIC WORKS MANAGEMENT & POLICY}, author={Rasdorf, William J. and Zhang, Guanghua and Hummer, Joseph E.}, year={2009}, month={Jan}, pages={265–277} }