*Article* **Measuring Landscape Albedo Using Unmanned Aerial Vehicles**

#### **Chang Cao 1,\*, Xuhui Lee 1,2,\*, Joseph Muhlhausen 3, Laurent Bonneau 4 and Jiaping Xu 5**


Received: 11 September 2018; Accepted: 13 November 2018; Published: 15 November 2018

**Abstract:** Surface albedo is a critical parameter in surface energy balance, and albedo change is an important driver of changes in local climate. In this study, we developed a workflow for landscape albedo estimation using images acquired with a consumer-grade camera on board unmanned aerial vehicles (UAVs). Flight experiments were conducted at two sites in Connecticut, USA and the UAV-derived albedo was compared with the albedo obtained from a Landsat image acquired at about the same time as the UAV experiments. We find that the UAV estimate of the visibleband albedo of an urban playground (0.037 ± 0.063, mean ± standard deviation of pixel values) under clear sky conditions agrees reasonably well with the estimates based on the Landsat image (0.047 ± 0.012). However, because the cameras could only measure reflectance in three visible bands (blue, green, and red), the agreemen<sup>t</sup> is poor for shortwave albedo. We sugges<sup>t</sup> that the deployment of a camera that is capable of detecting reflectance at a near-infrared waveband should improve the accuracy of the shortwave albedo estimation.

**Keywords:** Unmanned Aerial Vehicle (UAV); albedo; landscape; consumer-grade camera; radiometric calibration
