Academia.eduAcademia.edu

Figure 1 – uploaded by Daribel H Hernández

See full PDFdownloadDownload figure
Fic. 1. Orientation schematic for stations and geographic features of the region of study. Shading is topography (m MSL; terrain elevations given in legend in upper right). The SdB are indicated by white scalloping. Orange dot gives the location of KDFX WSR-88D, and blue dot gives the location of KDRT upper-air and surface station. Red line indicates track of continuous base reflectivity echoes at 0.5° tilt between 0728 and 1700 UTC 25 May 2015. Dark red circles are storm positions at 0900, 1200, and 1500 UTC, and black circle notes the position of Ciudad Acufia. topography of the SdB region (bounded by 28°-30°N, 101°-103°W) successively lower than in the control simulation: first to 75% of the original height, then to 50%, then finally to 25% (Fig. 2). This method is similar to the method of Barrett et al. (2009), but in this study, all elevations in the SdB region above a threshold were set to that threshold value. The thresholds were as fol- lows: 1878 m for the 75% experiment (that height was selected because 1878 m is 75% of the maximum height in the bounded region in the control simulation), 1252 m in the 50% experiment, and 626m in the 25% simula- tion. These adjustments effectively created smaller mountains in the 75% experiment, a tall mesa in the 50% experiment, and in the 25% experiment the entire SdB region resembled one continuous flat plain that gently sloped downward to the east (Fig. 2). Once the terrain elevations in the bounded region in the 1-km domain were flattened to their respective percentages, the edges of the bounded region were smoothed using a cubic kernel smoother to remove any abrupt height changes associated with the modification of the terrain. Then, the 1-km domain terrain was upscaled onto the 3-km domain grid using bilinear interpolation. In the 3-km

Figure 2 Fic. 1. Orientation schematic for stations and geographic features of the region of study. Shading is topography (m MSL; terrain elevations given in legend in upper right). The SdB are indicated by white scalloping. Orange dot gives the location of KDFX WSR-88D, and blue dot gives the location of KDRT upper-air and surface station. Red line indicates track of continuous base reflectivity echoes at 0.5° tilt between 0728 and 1700 UTC 25 May 2015. Dark red circles are storm positions at 0900, 1200, and 1500 UTC, and black circle notes the position of Ciudad Acufia. topography of the SdB region (bounded by 28°-30°N, 101°-103°W) successively lower than in the control simulation: first to 75% of the original height, then to 50%, then finally to 25% (Fig. 2). This method is similar to the method of Barrett et al. (2009), but in this study, all elevations in the SdB region above a threshold were set to that threshold value. The thresholds were as fol- lows: 1878 m for the 75% experiment (that height was selected because 1878 m is 75% of the maximum height in the bounded region in the control simulation), 1252 m in the 50% experiment, and 626m in the 25% simula- tion. These adjustments effectively created smaller mountains in the 75% experiment, a tall mesa in the 50% experiment, and in the 25% experiment the entire SdB region resembled one continuous flat plain that gently sloped downward to the east (Fig. 2). Once the terrain elevations in the bounded region in the 1-km domain were flattened to their respective percentages, the edges of the bounded region were smoothed using a cubic kernel smoother to remove any abrupt height changes associated with the modification of the terrain. Then, the 1-km domain terrain was upscaled onto the 3-km domain grid using bilinear interpolation. In the 3-km

Related Figures (14)

FIG. 2. Topography (shaded, m) for four sensitivity simulations performed using the WRF Model: (a) control with 100% elevations, (b) elevations reduced to 75%, (c) elevations reduced to 50%, and (d) elevations reduced to 25%. Vertical profiles (pressure, hPa) are below each panel, along 28.95°N and indicated by orange lines.
FIG. 2. Topography (shaded, m) for four sensitivity simulations performed using the WRF Model: (a) control with 100% elevations, (b) elevations reduced to 75%, (c) elevations reduced to 50%, and (d) elevations reduced to 25%. Vertical profiles (pressure, hPa) are below each panel, along 28.95°N and indicated by orange lines.
Fic. 3. Base reflectivity (dBZ) at 0.5° tilt from KDFX WSR-88D. All times in UTC (subtract 5 h from UTC for local hour) on 25 May 2015. Black arrows indicate the thunderstorm that produced the Ciudad Acufia tornado (tornado occurred between approximately 1045 and 1130 UTC).
Fic. 3. Base reflectivity (dBZ) at 0.5° tilt from KDFX WSR-88D. All times in UTC (subtract 5 h from UTC for local hour) on 25 May 2015. Black arrows indicate the thunderstorm that produced the Ciudad Acufia tornado (tornado occurred between approximately 1045 and 1130 UTC).
Fia. 4. In-cloud and cloud-to-ground lightning flashes detected per hour from 0700 to 1200 UTC 25 May 2015. Colors correspond to time of flash (UTC)—blue: 0700-0800, red: 0800-0900, green: 0900-1000, brown: 1000-1100, light blue: 1100-1200—and re- spective counts of flashes in the region shown reported in the table at the top of each panel. Positions of Ciudad Acufia, Del Rio upper- air station, and KDFX radar are indicated by circles. Topography height contoured every 100m. in the predawn light at approximately 1120 UTC (viewed by the authors, but not shown here). Addi- tionally, damage surveys from the Mexican National Water Commission [Comisi6n Nacional del Agua (CONAGUA)] indicated the tornado may have
Fia. 4. In-cloud and cloud-to-ground lightning flashes detected per hour from 0700 to 1200 UTC 25 May 2015. Colors correspond to time of flash (UTC)—blue: 0700-0800, red: 0800-0900, green: 0900-1000, brown: 1000-1100, light blue: 1100-1200—and re- spective counts of flashes in the region shown reported in the table at the top of each panel. Positions of Ciudad Acufia, Del Rio upper- air station, and KDFX radar are indicated by circles. Topography height contoured every 100m. in the predawn light at approximately 1120 UTC (viewed by the authors, but not shown here). Addi- tionally, damage surveys from the Mexican National Water Commission [Comisi6n Nacional del Agua (CONAGUA)] indicated the tornado may have
Fic. 5. (left) Base reflectivity (dBZ), (middle) base velocity (ms~'), and (right) correlation coefficient at 0.5° elevation angle from KDFX WSR-88D at (a)-(c) 1022, (d)-(f) 1032, (g)-(i) 1042, and (j)-(1) 1052 UTC 25 May 2015, zoomed to the storm position at each time.
Fic. 5. (left) Base reflectivity (dBZ), (middle) base velocity (ms~'), and (right) correlation coefficient at 0.5° elevation angle from KDFX WSR-88D at (a)-(c) 1022, (d)-(f) 1032, (g)-(i) 1042, and (j)-(1) 1052 UTC 25 May 2015, zoomed to the storm position at each time.
FIG. 6. As in Fig. 5, but for 1103, 1113, 1124, and 1134 UTC 25 May 2015.
FIG. 6. As in Fig. 5, but for 1103, 1113, 1124, and 1134 UTC 25 May 2015.
FIG. 7. Height at 500 hPa (black lines, contoured every 60 m starting at 5860 m in lower right), wind at 850 hPa (ms '), and 2-m dewpoint temperature (°C) at (a),(b) 0000; (c),(d) 0600; and (e),(f) 1200 UTC 25 May 2015. (b),(d),(£) Images are zoomed to the SdB region, indicated by yellow box in (a),(c), and (e). Position of Ciudad Acufia given by black dot in (b),(d), and (f). Reference wind vector for all panels given in (a). All data from RAP model analyses.
FIG. 7. Height at 500 hPa (black lines, contoured every 60 m starting at 5860 m in lower right), wind at 850 hPa (ms '), and 2-m dewpoint temperature (°C) at (a),(b) 0000; (c),(d) 0600; and (e),(f) 1200 UTC 25 May 2015. (b),(d),(£) Images are zoomed to the SdB region, indicated by yellow box in (a),(c), and (e). Position of Ciudad Acufia given by black dot in (b),(d), and (f). Reference wind vector for all panels given in (a). All data from RAP model analyses.
FIG. 8. (a) Radiosonde and (b) hodograph observations from KDRT at 0000 UTC 25 May (blue, 1900 LT 24 May) and 1200 UTC 25 May 2015 (red, 0700 LT 25 May). In (a), solid lines represent air temperature and dashed lines dewpoint temperature. In (a) and (b), wind speeds (ms7') are given. Calculated CAPE, CIN, precipitable water (PWAT), and lifted index (LIFT) provided in (a).
FIG. 8. (a) Radiosonde and (b) hodograph observations from KDRT at 0000 UTC 25 May (blue, 1900 LT 24 May) and 1200 UTC 25 May 2015 (red, 0700 LT 25 May). In (a), solid lines represent air temperature and dashed lines dewpoint temperature. In (a) and (b), wind speeds (ms7') are given. Calculated CAPE, CIN, precipitable water (PWAT), and lifted index (LIFT) provided in (a).
Fic. 9. Topography height (grayscale, m), 10-m wind (vector, ms '), and 10-m upslope flow component (positive in solid pink; negative in dashed pink; interval: 0.05 ms~') for (a)-(f) 0600-1100 UTC 25 May 2015 from RAP model analyses. Radar-based storm position at each hour indicated by dark red circle. Reference wind vector given in (a).
Fic. 9. Topography height (grayscale, m), 10-m wind (vector, ms '), and 10-m upslope flow component (positive in solid pink; negative in dashed pink; interval: 0.05 ms~') for (a)-(f) 0600-1100 UTC 25 May 2015 from RAP model analyses. Radar-based storm position at each hour indicated by dark red circle. Reference wind vector given in (a).
FIG. 10. As in Fig. 9, but blue solid (dashed) contours indicate horizontal mass convergence (divergence) at 10m, with data from RAP model analyses. Contour interval is every 2 x 10°-*kgm *s_!. Radar-based storm position at 0800-1100 UTC indicated by dark red circle. Reference wind vector given in (a).
FIG. 10. As in Fig. 9, but blue solid (dashed) contours indicate horizontal mass convergence (divergence) at 10m, with data from RAP model analyses. Contour interval is every 2 x 10°-*kgm *s_!. Radar-based storm position at 0800-1100 UTC indicated by dark red circle. Reference wind vector given in (a).
Fic. 11. CAPE (magenta contours every 500 J kg~'), 0-1-km SRH (shaded, m?s~*), and CIN (large dots indicate CIN < —100J kg™'; small dots indicate CIN between —50 and —100J kg” *; no dots indicate CIN > —50J kg ') for (a)-(f) 0600-1100 UTC 25 May 2015. SRH is contoured only where CAPE is positive. All data from RAP model analyses. Radar-based storm position at each hour indicated by dark red circle.
Fic. 11. CAPE (magenta contours every 500 J kg~'), 0-1-km SRH (shaded, m?s~*), and CIN (large dots indicate CIN < —100J kg™'; small dots indicate CIN between —50 and —100J kg” *; no dots indicate CIN > —50J kg ') for (a)-(f) 0600-1100 UTC 25 May 2015. SRH is contoured only where CAPE is positive. All data from RAP model analyses. Radar-based storm position at each hour indicated by dark red circle.
Fic. 12. (a) Upslope flow component at 10m (black curve; ms *) and horizontal mass Sonvergence (blue curve; kgm~*s~'). (b) CAPE (blue curve; Jkg~'), 0-1-km SRH (black curve; m?s~*), and CIN (red curve; J kg” '). (c) Highest base reflectivity (blue curve; dBZ) and horizontal wind difference (black curve;ms_'). All data from RAP model analyses. From 0000 to 0700 UTC 25 May 2015, all values are for the nine RAP model grid points closest to the point of CIN at 0728 UTC. From 0800 to 1200 UTC 25 May 2015, all values are for the nine RAP model grid points 25 km (two grid points) to the southeast of the thunderstorm location.
Fic. 12. (a) Upslope flow component at 10m (black curve; ms *) and horizontal mass Sonvergence (blue curve; kgm~*s~'). (b) CAPE (blue curve; Jkg~'), 0-1-km SRH (black curve; m?s~*), and CIN (red curve; J kg” '). (c) Highest base reflectivity (blue curve; dBZ) and horizontal wind difference (black curve;ms_'). All data from RAP model analyses. From 0000 to 0700 UTC 25 May 2015, all values are for the nine RAP model grid points closest to the point of CIN at 0728 UTC. From 0800 to 1200 UTC 25 May 2015, all values are for the nine RAP model grid points 25 km (two grid points) to the southeast of the thunderstorm location.
FIG. 13. Dewpoint temperature at 2 m (green and magenta lines, °C) and 10-m horizontal wind vectors from 1-km WRF Model simulations initialized at 0000 UTC 24 May 2015. Gray shading represents topography height (m). Light green lines correspond to dewpoint temperatures from 0° to 12.5°C. Magenta lines correspond to dewpoint temperatures from 15° to 22.5°C. Both light green and magenta lines are spaced at 2.5°C intervals. White contours are radar reflectivity every 10 dBZ. Positions of Ciudad Acufia, the Del Rio upper-air site, and the KDFX radar are indicated by small circles. Vertical cross sections presented in Fig. 15 are indicated by orange lines.
FIG. 13. Dewpoint temperature at 2 m (green and magenta lines, °C) and 10-m horizontal wind vectors from 1-km WRF Model simulations initialized at 0000 UTC 24 May 2015. Gray shading represents topography height (m). Light green lines correspond to dewpoint temperatures from 0° to 12.5°C. Magenta lines correspond to dewpoint temperatures from 15° to 22.5°C. Both light green and magenta lines are spaced at 2.5°C intervals. White contours are radar reflectivity every 10 dBZ. Positions of Ciudad Acufia, the Del Rio upper-air site, and the KDFX radar are indicated by small circles. Vertical cross sections presented in Fig. 15 are indicated by orange lines.
Fic. 14. Cumulative radar reflectivity swaths (white contours, every 10 dBZ) from 0600 to 1200 UTC 25 May 2015 for (a) control simulation with 100% topography and (b) experiment with 25% topography. Gray shading indicates topography height (m).
Fic. 14. Cumulative radar reflectivity swaths (white contours, every 10 dBZ) from 0600 to 1200 UTC 25 May 2015 for (a) control simulation with 100% topography and (b) experiment with 25% topography. Gray shading indicates topography height (m).
FIG. 15. Cross sections of mixing ratio (shaded, g kg~') and upward vertical velocity (dashed contours every 5 Pas” ', corresponding te every 0.5ms_') from 1-km WRF simulations with (a),(b) 100% topography and (c),(d) elevations reduced to 25%. Sections are along 28.95°N, from 102.95° through 99.55°W, as indicated by orange lines in Fig. 13.
FIG. 15. Cross sections of mixing ratio (shaded, g kg~') and upward vertical velocity (dashed contours every 5 Pas” ', corresponding te every 0.5ms_') from 1-km WRF simulations with (a),(b) 100% topography and (c),(d) elevations reduced to 25%. Sections are along 28.95°N, from 102.95° through 99.55°W, as indicated by orange lines in Fig. 13.
Related topics:
Atmospheric sciencesConvective cloudsMesoscale models
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved