# Atmosphere Boundary Layer Height (ABLH) Determination under Multiple-Layer Conditions Using Micro-Pulse Lidar

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## Abstract

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## 1. Introduction

## 2. Materials

#### 2.1. Micro Pulse Lidar (MPL)

#### 2.2. Description of Evaluation Data

_{2}, latent (H

_{2}O), and sensible heat flux ($H$) at 3.0 m AGL of 30 min intervals. The 32 m Micrometeorological tower at SACOL can provide wind speed measurements (014A-L, Met One) at 1, 2, 4, 8, 16, and 32 m with a temporal resolution of 30 min [48]. The wind speed at any two heights can approximately estimate the ground-layer wind shear ($S$). The observations of the surface sensible heat flux, momentum flux, and wind shear can be combined to estimate buoyance and shear productions ($H$ and $M=F\xb7S$) of ground-layer turbulent kinetic energy (TKE), which is a critical measure of the turbulent intensity.

## 3. Methods

#### 3.1. Traditional Techniques

#### 3.2. The Detailed Process for Improving the ABLH Determination

#### 3.3. The Evaluation Method

## 4. Results

#### 4.1. Comparisons between Lidar and Radiosonde Measurements of ABLH

#### 4.2. Diurnal Cycle of the ABLH

#### 4.2.1. Residual Layer Exists in the Morning

#### 4.2.2. ABLH Retrieval in Cloudy Situations

## 5. Discussion

## 6. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**(

**a**) A normalized relative backscatter (NRB) profile (left) and the shape of the Haar wavelet, (

**b**) the resulted covariance transform, ${w}_{f}$ as $\Delta h=600$.

**Figure 2.**(

**a**) An idealized backscatter profile, and (

**b**) a real case for the curve fitting procedure.

**Figure 3.**Major steps for determining the top limiter to eliminate the cloud effect on atmosphere boundary layer height (ABLH) retrieval in the new technique.

**Figure 4.**Vertical distributions of normalized relative lidar backscatter signal (NRB) (the first column), relative increase in NRB (the second column), gradient of NRB with the determined top limiter (the third column), and the gradient of NRB only below the lowest cloud layer (the last column) on typical situations: (

**a**) Cloud-free, observed at 14:15 local standard time (LST), 09 June 2007; (

**b**) one cloud layer is observed at 10:15 LST, 09 June 2007; (

**c**,

**d**) more than one cloud layers are observed, the lowest-altitude cloud in (

**c**) (at 13:45 LST, 28 October 2007) is decoupled from the ABL while in (

**d**) (at 10:15 LST, 28 October 2007) is within the ABL.

**Figure 5.**Vertical profiles of (

**a**) potential temperature (theta) and specific humidity (q) at Yuzhong site, (

**b**) lidar NRB at SACOL (Semi-Arid Climate observatory and Laboratory). The ABLH determined using different methods are marked in each panel. The profile was observed at 12:00 UTC on 17 January 2011 (In cloud-free condition).

**Figure 6.**Similar to Figure 5, but for a cloudy case (12:00 UTC on 3 September 2010). Vertical profiles of (

**a**) potential temperature (theta) and specific humidity (q) at Yuzhong site, (

**b**) or (

**c**) lidar NRB at SACOL, the ABLH retrieved by the Haar wavelet method (HM) and curve fitting method (CFM) (

**b**) directly, (

**c**) below the determined top limiter.

**Figure 7.**Comparison between radiosonde-determined (vertical coordinate) and lidar measurement (horizontal coordinate) of ABLH by HM (

**a**) or CFM (

**b**) on 41 cases in cloud-free situations. The correlation coefficients are represented by R. The black solid line is the 1:1 line.

**Figure 8.**Similar to Figure 7, but in cloudy situations. The blue open dots represent the comparison results of ABLH determined by theta gradient (vertical coordinate) and determined by HM (

**a**) or CFM (

**b**) (horizon coordinate) without height limitation, the red stars indicate the comparison results after the top limiter is given for HM and CFM. R represents the correlation coefficients, blue represents no top limiter, and red represents with the top limiter.

**Figure 9.**Lidar measurements of ABLH over SACOL on 28 July 2007. (

**a**) Time-height cross-section of the NRB, red solid line is the determined top altitude limiter, (

**b**) ABLH determined directly from the HM and CFM, (

**c**) ABLH determined from the HM and CFM below the top limiter. (

**d**) Diurnal cycles of buoyancy production and shear production for ground-layer turbulent kinetic energy (TKE), (

**e**) time-height cross-section of equivalent potential temperature (${\theta}_{e}$).

**Figure 10.**Same as in Figure 9, but on 9 June 2007.

**Figure 11.**Same as in Figure 9, but on 28 October 2007.

**Figure 12.**Same as in Figure 9, but on 12 June 2007. The radiometrics profiling radiometer data quality were seriously affected by clouds and there was no equivalent potential temperature data available.

**Table 1.**Correlation coefficients (R), absolute height differences (mean and standard deviation (std) in km) between ABLH determined by theta gradient and by the Haar wavelet covariance transform method (HM) or curve fitting method (CFM) in different situations, as well as mean value of relative absolute differences relative to theta-gradient-determined ABLH (rd, in 100%).

Situations | Method | R | mean | std | rd |
---|---|---|---|---|---|

Cloud-free situation | HM | 0.96 | 0.14 | 0.11 | 10.5 |

CFM | 0.94 | 0.17 | 0.13 | 12.3 | |

Cloudy situation (without top limiter) | HM | 0.09 | 0.83 | 0.90 | 66.1 |

CFM | 0.11 | 0.67 | 0.64 | 53.7 | |

Cloudy situation (with top limiter) | HM | 0.74 | 0.28 | 0.24 | 22.3 |

CFM | 0.79 | 0.22 | 0.18 | 17.2 |

**Table 2.**Correlation coefficients (R) and absolute height differences (mean and standard deviation (std) in km) between ABLH retrieved by HM and CFM based on lidar data of four selected cases.

Date | R | mean | std |
---|---|---|---|

2007.07.28 | 0.998 | 0.25 | 0.21 |

2007.06.09 | 0.993 | 0.32 | 0.37 |

2007.10.28 | 0.993 | 0.13 | 0.22 |

2007.06.12 | 0.997 | 0.16 | 0.15 |

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**MDPI and ACS Style**

Dang, R.; Yang, Y.; Li, H.; Hu, X.-M.; Wang, Z.; Huang, Z.; Zhou, T.; Zhang, T.
Atmosphere Boundary Layer Height (ABLH) Determination under Multiple-Layer Conditions Using Micro-Pulse Lidar. *Remote Sens.* **2019**, *11*, 263.
https://doi.org/10.3390/rs11030263

**AMA Style**

Dang R, Yang Y, Li H, Hu X-M, Wang Z, Huang Z, Zhou T, Zhang T.
Atmosphere Boundary Layer Height (ABLH) Determination under Multiple-Layer Conditions Using Micro-Pulse Lidar. *Remote Sensing*. 2019; 11(3):263.
https://doi.org/10.3390/rs11030263

**Chicago/Turabian Style**

Dang, Ruijun, Yi Yang, Hong Li, Xiao-Ming Hu, Zhiting Wang, Zhongwei Huang, Tian Zhou, and Tiejun Zhang.
2019. "Atmosphere Boundary Layer Height (ABLH) Determination under Multiple-Layer Conditions Using Micro-Pulse Lidar" *Remote Sensing* 11, no. 3: 263.
https://doi.org/10.3390/rs11030263