# Estimations of the Mexicali Valley (Mexico) Mixing Height

^{1}

^{2}

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## Abstract

**:**

## 1. Introduction

## 2. Study Area

## 3. Materials and Methods

#### 3.1. Meteorological Campaigns

#### 3.1.1. Surface Meteorological Measurements

_{0}), Monin–Obukhov length (L), and turbulent kinetic energy (ε), among others. Using 1-min sets of data, we carried out two rotations on the ordinary velocity components (v

_{x}, v

_{y}, v

_{z}) to obtain the mean streamwise velocity $\left(u,0,0\right)$ and the turbulent fluctuations $\left(\tilde{u},\tilde{v},\tilde{w}\right)$ and $\tilde{T}$ of the velocity components and (sonic) temperature (T). Then, we used the following equations to estimate the turbulent parameters from the covariance between the turbulent fluctuations [14]:

_{p}are the density and specific heat of the air, k is the von Karman constant, and g is the gravity acceleration.

#### 3.1.2. Atmospheric Soundings

#### 3.2. Estimation Methods

_{k}was the sum of the values of temperature at z

_{k-1}multiplied by 0.25, at the z

_{k}of interest multiplied by 0.5, and at z

_{k+1}multiplied by 0.25:

#### 3.2.1. Convective Boundary Layer

#### The Parcel Method

#### Gradient Methods

#### Slab Model of CBL and the Least-Squares Fitting Approach to the Mixing Height

_{s}of the surface layer is infinitesimal (negligible).

_{dew}), and these basic profiles allow us to calculate the specific humidity q and the virtual potential temperature $\overline{\theta}$ using standard relations [20,22].

#### Covariance Method

#### 3.2.2. Stable Boundary Layer

#### Parametrizations of the Turbulent SBL

_{BV}, defined by the Brunt-Vaisala frequency, instead of 1/f or where the diagnostic formulae considering the bulk structure of the SBL are based on the assumption that turbulence production must vanish at the SBL top and the Richardson number must, therefore, exceed its critical value [10]. However, these and other available methods (see [10] for a review) involve information not available from radiosondes, such as cloud base height, micrometeorological covariance statistics, or turbulence flux profiles.

^{−5}s

^{−1}. Then, Z1972 became to

_{m}in meters if ${u}_{*}$ is in m/s, and L is in meters. Friction velocity in A1981S is limited to $0.05<{u}_{*}<1.2$ m/s [50].

#### Surface-Based Inversions

#### 3.2.3. Estimation of Mixing Height from the Sensible Heat Flux

_{0}in the integral of Equation (15) denotes the instance when H

_{0}changes sign from negative to positive (at the sunrise). When t = t

_{0}, we have ${h}_{m}\left({t}_{0}\right)=a$. Then, the constant a represents the value of mixing height at the sunrise. The upper limit t is the time of interest, for which, we want to evaluate the mixing height, t

_{0}< t ≤ t

_{m}+ 2 h. t

_{m}is the time when the sensible heat flux reaches its maximum value [52]. From the standpoint of YDBB, the mixing height gets the most significant value when t ≈ t

_{m}+ 2 h, approximately. However, in [52], the authors underlined that it might occur (in northern Wisconsin) that the weather is generally transparent or partly cloudy on days when maximum mixing height is reached 4 h after the maximum ${H}_{0}$. Moreover, with clear skies in the summertime, the mixing layer can continue to grow for 5 or 6 h after the maximum ${H}_{0}$.

#### 3.2.4. The Time Evolution of the Mixing Height

_{0}< t ≤ t

_{m}+ 2 h and 0 otherwise. The function h

_{s}is one convenient parametrization (N1972, Z1981, A1981, or any other) that allows estimating the nocturnal value of h

_{m}.

## 4. Results and Discussion

#### 4.1. Surface Meteorological Data

_{0}> 0 are consistent with the observations of ζ < 0 and μ < 0, corroborating the unstable atmospheric conditions. On average, H

_{0}reached its maximum at noon, independently of the seasonal period, with values of 239, 123, and 96 W/m

^{2}in the summer, winter, and autumn RS-campaigns, respectively. At midday, the surface upward turbulent transport of thermal energy was more abundant in summer than in winter and autumn campaigns.

_{0}at noon was higher in winter than in autumn, but this is reflecting only that on the day January 28, the average value of H

_{0}registered from 10:00 LST to 13:00 LST was 142 W/m

^{2}against the average of 88 W/m

^{2}registered during the rest of the campaign. Moreover, we can observe that the hourly trends of H

_{0}averaged over the month revealed maximums of 205 W/m

^{2}in summer, 82 W/m

^{2}in winter, and 106 W/m

^{2}in autumn at noon, which are consistent with the expected seasonal differences. Accordingly, we expect that the convective mixing heights reveal the seasonal differences correctly.

#### 4.2. Vertical Profiles of Temperature

#### 4.3. Estimation of the Convective Mixing Height with the LSVA, GM, CM, and PM

_{dew}) vertical profiles from the RS. In Table 4, Table 5 and Table 6, we labeled the application of the LSVA and GM as LSVA/VPT, GM/VPT, LSVA/SH, and GM/SH. The CM requires both profiles, VPT and SH. The PM was applied directly to the RS and dry adiabatic temperature profiles. We measured the surface temperature in situ with an RTD thermometer (RM Young, model 43347) at 12 m above ground, with 1 Hz sampling rate and 1-h averaging times.

_{0}> 0, which indicate unstable atmospheric conditions near the ground. The soundings of the 18:00 LST were performed under surface conditions with ζ > 0, μ > 0, and H

_{0}< 0, which indicate stable conditions. However, as we can observe, the near-surface temperature lapse rates of these RS were superadiabatic, indicating that they found unstable conditions in the first 100–200 m above ground. The radiosoundings of the 18:00 LST were carried out during the transition period of the sunset, which explains the small positive values of the stability parameters and the small negative values of H

_{0}.

#### 4.4. Estimation of the Stable Boundary Layer Height

#### 4.4.1. Summer 2010 Campaign

_{0}= −9 W/m

^{2}, ζ = 0.525, and μ = 59 (Table 7). These observations indicate that the 00:00 LST soundings were done under very stable atmospheric conditions. The near-surface lapse rates of the temperature profiles were subadiabatic (Γ = −0.0027 K/m, on average). We used N1981, Z1972S, and A1981S to estimate the Mexicali Valley midnight stable mixing height from the friction velocity and the Monin–Obukhov length. Table 7 and Figure 11 summarize the results.

#### 4.4.2. Winter 2012 and Autumn 2016 Campaigns

#### 4.5. Estimation of the Mixing Layer Growth with the YDBB Model

_{0}(t). We determined the sensible heat flux as the covariance between the turbulent fluctuations of temperature and the vertical wind component measured with a 3D ultrasonic anemometer at z = 12 m, using Equation (2).

_{0}data collected during the surface meteorological campaigns and the estimations of the convective and stable mixing heights, the parameters a and b of the YDBB model were determined. In the case of the summer 2010 campaign (the longer one), the results for the convective conditions included 14 estimations of the mixing height for the 06:00 LST (6 RS), 12:00 LST (6 RS), and 15:00 LST (2 RS). For the winter 2012 campaign, we obtained only three estimations of the convective mixing height for the 12:00 LST. For the autumn 2016 campaign, we had estimations of convective mixing height for the 08:00 LST (1 RS), 12:00 LST (1 RS), 14:00 LST (3 RS), and 15:00 LST (2 RS). No RS soundings were available for sunrise during the winter and autumn campaigns. Therefore, we used the friction velocity surface measurements to estimate the mixing height at 07:00 LST (each day of these campaigns) with the diagnostic parametrization A1981S. In Table 10, we presented the results obtained for the YDBB model parameters, including the determination coefficient R

^{2}. In Figure 15, we showed the results of the application of the YDBB model (Equation (16)) to calculate the mixing height for all hours during the sounding campaigns.

## 5. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

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**Figure 2.**Idealized profiles of virtual potential temperature (VPT) and specific humidity (SH) from the standpoint of the slab model of the convective boundary layer (CBL).

**Figure 3.**Slab model for the vertical profile of VTP under convective conditions. The thickness of both the entrainment zone and the surface layer is assumed infinitesimal (negligible). The straight dark lines represent the model VPT profile. We used a similar model for the SH profile.

**Figure 4.**Hourly behaviors of the minimum, mean, and maximum values of temperature, relative humidity, and wind speed during the Cerro Prieto (Mexicali) summer, winter, and autumn campaigns.

**Figure 5.**Hourly behaviors of the minimum, mean, and maximum values of sensible heat flux, friction velocity, and the stability parameters during the Cerro Prieto (Mexicali) summer, winter, and autumn campaigns.

**Figure 6.**Temperature profiles obtained from the RS during daylight conditions. (

**a**) 06:00 LST, (

**b**) 12:00 LST, (

**c**) 15:00 LST, and (

**d**) 18:00 LST from the summer RS campaign; (

**e**) 12:00 LST from the winter campaign; and (

**f**) 12:00 LST, (

**g**) 14:00 LST, and (

**h**) 15:00 LST from the autumn campaign. The solid line represents the average profile. We carried out only one RS at 12:00 LST during the autumn campaign.

**Figure 7.**Application of the estimation methods to the VPT, SH, and T profiles of the 12:00 LST of the days 18, 20, 21, 23, and 26 of July 2010. First column: LSVA/VPT and GM/VPT. Second column: LSVA/SH and GM/SH. Third column: CM. Fourth column: PM.

**Figure 8.**Application of the LSVA, GM, CM, and PM to the VPT, SH, and T profiles of the 12:00 LST of the days 26, 28, and 29 of January 2012. First column: LSVA/VPT and GM/VPT. Second column: LSVA/SH and GM/SH. Third column: CM. Fourth column: PM.

**Figure 9.**Application of the LSVA, GM, CM, and PM to the VPT, SH, and T profiles of the 12:00 LST of October 12, 2016. First column: LSVA/VPT and GM/VPT. Second column: LSVA/SH and GM/SH. Third column: CM. Fourth column: PM.

**Figure 10.**Estimations of the convective mixing height with the LSVA/VPT, GM/VPT, LSVA/SH, GM/SH, CM, and PM. (

**a**) Summer 2010, (

**b**) winter 2012, and (

**c**) autumn 2016. The graphs also show the mean value (solid line) over all the methods. The estimations obtained with the SH profile of the 12:00 LST sounding of 29 January 2012, reflected an atypical behavior of the specific humidity profile, and we discarded them when calculating the mixing height mean value.

**Figure 11.**Estimations of the Mexicali Valley mixing height under the 00:00 LST stable atmospheric conditions during the summer 2010 campaign. We observe that the A1981S parametrization, Equation (14), overestimated the mixing height in comparison with the other two models during very stable conditions (μ > 50).

**Figure 12.**Estimation of the height of the stable boundary layer (SBL) of the Mexicali Valley from the surface-based inversions during the winter 2012 campaign. The graphs show the evolution of the surface-based inversion (SBI) from the first hours after sunset to 1 h before sunrise of the next day.

**Figure 13.**Estimation of the height of the SBL of the Mexicali Valley from the surface-based inversions during the autumn 2016 campaign. The graphs illustrate the change of the SBI from the sunset to 1 h before sunrise of the next day.

**Figure 14.**Breaking-off of the surface-based inversion developed from the sunset of 14 October to the early morning of 15 October, during the summer 2010 campaign in the Mexicali Valley. As we observed in Table 6, the radiosonde (RS) profile 20161015-08:00 revealed a subadiabatic near-surface temperature lapse rate of Γ = −0.0046 K/m.

**Figure 15.**Application of the Yi, Davis, Berger, and Bakwin (YDBB) model described by Equation (16) to estimate the hourly growth of the mixing height throughout the periods of (

**a**)17–28 July 2010, (

**b**) 25–29 January 2012, and (

**c**) 11–15 October 2016. We also presented the mixing height estimations with the LSVA/VPT, GM/VPT, and PM methods. The abscissae represent the number of hours past from the start (expressed by the Julian day) of the RS campaign.

**Table 1.**Number and launching time of the soundings carried out during the campaigns. The color of the cells indicates the sunlight conditions during the radiosoundings (RS): yellow cells indicate diurnal RS, whereas blue cells indicate nocturnal RS.

Campaign | 00:00 LST | 06:00 LST | 08:00 LST | 11:00 LST | 12:00 LST | 14:00 LST | 15:00 LST | 18:00 LST | 21:00 LST | Total |
---|---|---|---|---|---|---|---|---|---|---|

Summer 2010 | 5 | 6 | 0 | 1 | 5 | 0 | 2 | 6 | 0 | 25 |

Winter 2012 | 3 | 3 | 0 | 0 | 3 | 0 | 0 | 2 | 2 | 13 |

Autumn 2016 | 0 | 3 | 1 | 0 | 1 | 3 | 2 | 4 | 0 | 14 |

**Table 2.**Stability classes, as suggested by Arya [17]. Sonic at z = 12 m.

Parameter | Extremely Unstable | Very Unstable | Moderately Unstable | Near Neutral Unstable | Neutral | Near Neutral Stable | Moderately Stable | Very Stable | Extremely Stable |
---|---|---|---|---|---|---|---|---|---|

$\mu ={u}_{*}/fL$ | $\langle -\infty ,-100\rangle $ | $[-100,-50\rangle $ | $[-50,-10\rangle $ | $[-10,0\rangle $ | 0 | $\langle 0,10]$ | $\langle 10,50]$ | $\langle 50,100]$ | $\langle 100,\infty \rangle $ |

**Table 3.**Stable mixing height diagnostic algorithms. The equations give stable mixing height (${h}_{m}$) as a function of friction velocity (${u}_{*}$) Monin–Obukhov length (L), and the Coriolis parameter (f).

Model | Authors | ID |
---|---|---|

${h}_{m}=0.3\left[\frac{\left({u}_{*}/f\right)}{1+1.9\left({h}_{m}/L\right)}\right]$ | Nieuwstadt [38,42] | N1981 |

${h}_{m}=a{\left(\frac{{u}_{*}L}{f}\right)}^{1/2}$ | Zilitinkevich [35]. Arya [17]: a = 0.74. Mahrt, Andre, and Heald [39]: a = 0.6. Nieuwstadt [41]: a = 0.4. | Z1972 |

${h}_{m}=a\left(\frac{{u}_{*}}{f}\right)$ | Arya [17]: a = 0.142. Mahrt, Andre & Heald [39]: a = 0.06. | A1981 |

Summer 2010 | Mixing Height Estimations (m) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

DATE-TIME | $\mathit{z}/\mathit{L}$ | ${\mathit{u}}_{*}/\mathit{f}\mathit{L}$ | Γ (K/m) | H_{0} (W/m^{2}) | LSVA/VPT | GM/VPT | LSVA/SH | GM/SH | CM | PM | MEAN |

20100718-06:00 | −0.111 | −33 | −0.008 | 32 | 460 | 430 | 460 | 430 | 450 | 413 | 441 |

20100720-06:00 | −0.097 | −34 | −0.006 | 45 | 560 | 570 | 560 | 550 | 570 | 445 | 543 |

20100721-06:00 | −0.171 | −45 | −0.008 | 35 | 530 | 490 | 510 | 550 | 530 | 455 | 511 |

20100723-06:00 | −0.853 | −114 | −0.008 | 23 | 290 | 270 | 280 | 250 | 270 | 255 | 269 |

20100726-06:00 | −0.047 | −24 | −0.006 | 43 | 660 | 670 | 630 | 690 | 670 | 510 | 638 |

20100728-06:00 | −0.221 | −80 | −0.010 | 99 | 550 | 530 | 560 | 590 | 630 | 469 | 555 |

Average Values | −0.250 | −55 | −0.008 | 46 | 508 | 493 | 500 | 510 | 520 | 450 | 497 |

20100728-11:00 | −0.448 | −129 | −0.012 | 189 | 1150 | 1090 | 1090 | 1090 | 1110 | 1166 | 1116 |

20100718-12:00 | −1.196 | −261 | −0.010 | 257 | 1070 | 1070 | 1080 | 1010 | 1090 | 1580 | 1150 |

20100720-12:00 | −0.242 | −115 | −0.011 | 231 | 1290 | 1250 | 1260 | 1250 | 1270 | 1366 | 1281 |

20100721-12:00 | −0.185 | −108 | −0.010 | 299 | 1060 | 990 | 1180 | 1250 | 1010 | 1001 | 1082 |

20100723-12:00 | −1.453 | −310 | −0.010 | 162 | 1410 | 1050 | 1710 | 1690 | 1710 | 1674 | 1541 |

20100726-12:00 | −0.353 | −146 | −0.011 | 273 | 1350 | 1150 | 1170 | 1290 | 1270 | 1457 | 1281 |

Average Values | −0.646 | −178 | −0.0106 | 235 | 1222 | 1100 | 1248 | 1263 | 1243 | 1374 | 1242 |

20100720-15:00 | −0.098 | −61 | −0.010 | 207 | 1270 | 790 | 1330 | 1410 | 1430 | 1410 | 1273 |

20100728-15:00 | −0.140 | −68 | −0.010 | 133 | 1630 | 1810 | 1470 | 1770 | 1730 | 799 | 1535 |

Average Values | −0.119 | −65 | −0.010 | 170 | 1450 | 1300 | 1400 | 1590 | 1580 | 1105 | 1404 |

20100717-18:00 | −0.003 | −2 | −0.010 | 5 | 490 | 470 | 450 | 470 | 470 | 457 | 468 |

20100718-18:00 | 0.009 | 4 | −0.010 | −5 | 560 | 530 | 470 | 530 | 550 | 532 | 529 |

20100720-18:00 | 0.034 | 11 | −0.010 | −9 | 400 | 390 | 400 | 390 | 410 | 382 | 395 |

20100721-18:00 | 0.028 | 11 | −0.010 | −11 | 690 | 650 | 620 | 630 | 650 | 526 | 628 |

20100723-18:00 | 0.149 | 32 | −0.010 | −15 | 440 | 370 | 330 | 370 | 370 | 350 | 372 |

20100726-18:00 | 0.057 | 19 | −0.010 | −15 | 570 | 590 | 450 | 550 | 450 | 407 | 503 |

Average Values | 0.046 | 12 | −0.010 | −8 | 525 | 500 | 453 | 490 | 483 | 442 | 482 |

Winter 2012 | Mixing Height Estimations (m) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

DATE-TIME | $\mathit{z}/\mathit{L}$ | ${\mathit{u}}_{*}/\mathit{f}\mathit{L}$ | Γ (K/m) | H_{0} (W/m^{2}) | LSVA/VPT | GM/VPT | LSVA/SH | GM/SH | CM | PM | MEAN |

20120126-12:00 | −1.255 | −208 | −0.009 | 72 | 330 | 310 | 380 | 370 | 370 | 330 | 348 |

20120128-12:00 | −0.204 | −87 | −0.010 | 166 | 1100 | 1230 | 1060 | 1330 | 1330 | 1204 | 1209 |

20120129-12:00 | −0.781 | −185 | −0.010 | 114 | 720 | 730 | 2100 | 2090 | 2110 | 668 | 706 |

Average Values | −0.747 | −160 | −0.009 | 117 | 717 | 757 | 1180 | 1263 | 1270 | 734 | 754 |

Autumn 2016 | Mixing Height Values (m) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

DATE-TIME | $\mathit{z}/\mathit{L}$ | ${\mathit{u}}_{*}/\mathit{f}\mathit{L}$ | Γ (K/m) | H_{0} (W/m^{2}) | LSVA/VPT | GM/VPT | LSVA/SH | GM/SH | CM | PM | MEAN |

20161015-08:00 | −1.293 | −195 | −0.005 | 57 | 190 | 130 | 280 | 270 | 190 | 130 | 198 |

Average Values | −1.293 | −195 | −0.005 | 57 | 190 | 130 | 280 | 270 | 190 | 130 | 198 |

20161012-12:00 | −0.677 | −148 | −0.010 | 85 | 1180 | 1190 | 1090 | 1270 | 1290 | 1147 | 1195 |

Average Values | −0.677 | −148 | −0.010 | 85 | 1180 | 1190 | 1090 | 1270 | 1290 | 1147 | 1195 |

20161012-14:00 | −0.887 | −129 | −0.010 | 52 | 1490 | 1570 | 1410 | 1470 | 1390 | 1306 | 1439 |

20161013-14:00 | −3.127 | −307 | −0.010 | 64 | 1410 | 1430 | 1410 | 1510 | 1430 | 1367 | 1426 |

20161015-14:00 | −0.255 | −77 | −0.010 | 70 | 1140 | 1090 | 1050 | 1050 | 1050 | 1026 | 1068 |

Average Values | −1.423 | −171 | −0.010 | 62 | 1347 | 1363 | 1290 | 1343 | 1290 | 1233 | 1311 |

20161011-15:00 | −0.655 | −129 | −0.010 | 55 | 1240 | 1310 | 1250 | 1270 | 1270 | 1207 | 1258 |

20161014-15:00 | −0.338 | −81 | −0.010 | 77 | 1480 | 1550 | 1210 | 1270 | 1250 | 1290 | 1342 |

Average Values | −0.497 | −105 | −0.010 | 66 | 1360 | 1430 | 1230 | 1270 | 1260 | 1249 | 1300 |

**Table 7.**The summer stable mixing height of the Mexicali Valley estimated with the surface mean values of friction velocity and Monin–Obukhov length according to the N1981, Z1972S, and A1981S. Here, we also included the mean surface values of the stability parameters and sensible heat flux, and the near-surface temperature lapse rate of the radiosonde (RS).

Summer 2010 | Mixing Height (m) | |||||||
---|---|---|---|---|---|---|---|---|

DATE-TIME | $\mathit{z}/\mathit{L}$ | ${\mathit{u}}_{*}/\mathit{f}\mathit{L}$ | Γ (K/m) | Ho (W/m^{2}) | N1981 | Z1972S | A1981S | Mean |

20100718-00:00 | 0.228 | 38 | −0.0041 | −9 | 155 | 262 | 246 | 221 |

20100720-00:00 | 0.547 | 68 | −0.0024 | −11 | 96 | 154 | 202 | 151 |

20100721-00:00 | 0.666 | 50 | −0.0003 | −4 | 64 | 121 | 140 | 109 |

20100723-00:00 | 0.871 | 86 | −0.0018 | −11 | 78 | 125 | 180 | 128 |

20100726-00:00 | 0.313 | 52 | −0.0050 | −12 | 126 | 208 | 235 | 190 |

Average Values | 0.525 | 59 | −0.0027 | −9 | 104 | 174 | 201 | 160 |

**Table 8.**The nocturnal stability conditions of the Mexicali Valley during the winter 2012 campaign. The height of the stable boundary layer (SBL) estimated from surface-based inversion.

Winter 2012 | |||||
---|---|---|---|---|---|

DATE-TIME | $\mathit{z}/\mathit{L}$ | ${\mathit{u}}_{*}/\mathit{f}\mathit{L}$ | Γ (K/m) | H_{0} (W/m^{2}) | SBI (m) |

20120126-00:00 | 2.225 | 85 | 0.0092 | −4 | 65 |

20120128-00:00 | 0.276 | 74 | 0.0189 | −37 | 100 |

20120129-00:00 | 1.290 | 211 | 0.0029 | −46 | 160 |

Average Values | 1.264 | 123 | 0.0103 | −29 | 108 |

20120126-06:00 | 1.621 | 153 | 0.0287 | −12 | 240 |

20120128-06:00 | 0.558 | 110 | 0.0022 | −35 | 135 |

20120129-06:00 | 2.388 | 253 | 0.0042 | −26 | 174 |

Average Values | 1.522 | 172 | 0.0117 | −24 | 183 |

20120126-18:00 | 1.316 | 89 | 0.0011 | −6 | 50 |

20120128-18:00 | 2.462 | 213 | 0.0031 | −18 | 55 |

Average Values | 1.889 | 151 | 0.0021 | −12 | 53 |

20120125-21:00 | 6.264 | 70 | 0.0090 | −2 | 88 |

20120127-21:00 | 0.444 | 86 | 0.0146 | −25 | 142 |

Average Values | 3.354 | 78 | 0.0118 | −13 | 115 |

**Table 9.**The nocturnal stability conditions of the Mexicali Valley during the autumn 2016 campaign. The height of the SBL estimated from surface-based inversion.

Autumn 2016 | |||||
---|---|---|---|---|---|

DATE-TIME | $\mathit{z}/\mathit{L}$ | ${\mathit{u}}_{*}/\mathit{f}\mathit{L}$ | Γ (K/m) | H_{0} (W/m^{2}) | SBI (m) |

20161012-06:00 | 0.435 | 58 | 0.0102 | −2 | 400 |

20161013-06:00 | 1.029 | 28 | 0.0119 | −1 | 330 |

20161014-06:00 | 0.595 | 47 | 0.0237 | −3 | 380 |

Average Values | 0.686 | 44 | 0.0153 | −2 | 370 |

20161011-18:00 | 0.165 | 47 | 0.0017 | −27 | 98 |

20161012-18:00 | 2.319 | 41 | 0.0044 | −1 | 50 |

20161013-18:00 | 0.659 | 68 | 0.0133 | −16 | 100 |

20161014-18:00 | 0.044 | 18 | 0.0040 | −24 | 280 |

Average Values | 0.797 | 43 | 0.0058 | −17 | 132 |

**Table 10.**Parameters of the Yi, Davis, Berger, and Bakwin (YDBB) model obtained from measurements of H

_{0}and estimations of mixing height from convective atmospheric soundings and surface measurements of friction velocity.

Campaign | a (m) | b (m s kg^{−1/2}) | R^{2} |
---|---|---|---|

Summer (17–28 July 2010) | 277.34 | 28.71 | 0.88 |

Winter (25–29 January 2012) | 129.71 | 36.38 | 0.83 |

Autumn (11–15 October 2016) | 75.27 | 51.22 | 0.89 |

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Salcido, A.; Celada-Murillo, A.-T.; Carreón-Sierra, S.; Castro, T.; Peralta, O.; Salcido-González, R.-S.; Hernández-Flores, N.; Tamayo-Flores, G.-A.; Martínez-Flores, M.-A.
Estimations of the Mexicali Valley (Mexico) Mixing Height. *Atmosphere* **2020**, *11*, 505.
https://doi.org/10.3390/atmos11050505

**AMA Style**

Salcido A, Celada-Murillo A-T, Carreón-Sierra S, Castro T, Peralta O, Salcido-González R-S, Hernández-Flores N, Tamayo-Flores G-A, Martínez-Flores M-A.
Estimations of the Mexicali Valley (Mexico) Mixing Height. *Atmosphere*. 2020; 11(5):505.
https://doi.org/10.3390/atmos11050505

**Chicago/Turabian Style**

Salcido, Alejandro, Ana-Teresa Celada-Murillo, Susana Carreón-Sierra, Telma Castro, Oscar Peralta, Rogelio-Sebastián Salcido-González, Nicasio Hernández-Flores, Gustavo-Adolfo Tamayo-Flores, and Marco-Antonio Martínez-Flores.
2020. "Estimations of the Mexicali Valley (Mexico) Mixing Height" *Atmosphere* 11, no. 5: 505.
https://doi.org/10.3390/atmos11050505