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Topographic effect on calculating solar radiation

2024.6.4

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경윤서, 박정훈, 백소진, 이정호

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Contents

1. Introduction
2. Material and Methods
3. Result
4. Discussion

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Introduction

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1.1 Geometry and radiation flux

1. Introduction

Concept of geometry (Lecture 3)

Upwelling and downwelling radiation flux (Lecture 10)

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1.2 Natural surface and topographic bias

1. Introduction

Direct flux and Diffuse flux

(Lecture 12)

Langley Plot (Lecture 12)

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1.2 Natural surface and Topographic bias

1. Introduction

Bulk property (Lecture 6)

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관악산

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Material and Methods

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2.1 Schematic Diagram

2. Material and Methods

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2.2 Preparation of input data

2. Material and Methods

• Estimating Shortwave Irradiance

• Digital Elevation Model (DEM)

: potential direct irradiance under clear‐sky

conditions

: Incident extraterrestrial radiation normal

to the solar beam

: Direct beam solar irradiance

: Diffuse beam solar irradiance

: Atmospheric transmittance

: optical air mass

(Ref: ESA copernicus-mission digital elevation model)

(Campbell et al., 1998)

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2.3 Calculating Geographic Variable

2. Material and Methods

D

Slope(S)

: 경사도

Aspect(A)

: slope의 방향

- Calculating slope, aspect

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직달일사가 주변 지형에 의해 가려지는지 여부

각 방위각에 대해서 주변 pixel과 이루는 고도각 중 최댓값

(방위각 5°마다 구함)

pixel에서 볼 수 있는 하늘의 비율

2.3 Calculating Geographic Variable

2. Material and Methods

sun ray 방향의 hi와

90°-solar zenith angle을 비교

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2.3 Calculating Geographic Variable

2. Material and Methods

DEM

Slope

Aspect

Skyview factor

Horizontal angle

1. Direct Irradiance

2.4 Calculating Irradiance

2. Material and Methods

* isotropic diffuse 가정

2. Diffuse Irradiance

2.4 Calculating Irradiance

2. Material and Methods

3. Reflected Irradiance

c.f) Lambertian reflection

P: 3 x 3

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2. Material and Methods

2.4 Study Site

다양한 지형을 가지고 있는

철원 논밭

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• Lat, Lon: �38.2013, 127.2505

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• Resolution: �30m (12km by 12km)

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Result

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Plot 2

Plot 1

Plot 3

3. Result

3.1 Result of Topographic correction

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Plot 2

Plot 1

Plot 3

3. Result

3.2 Components determining Topographic effect

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Discussion

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Plot 2

Plot 1

Plot 3

4. Discussion

4.1 Importance of solar radiation estimation

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Plot 2

Plot 1

Plot 3

4. Discussion

4.2 Significance of topographic correction

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Plot 2

Plot 1

Plot 3

4. Discussion

4.3 Resolution Dependency of Topographic correction

The Solar net radiation from ERA5-Land (a) and the downscaled dataset (b) for 30 June 2018. The maps shown depict a large part of western Europe covering France, Germany and Italy (Rains, D et al,. 2024).

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Thank you