# Bristow-Campbell model

### Description

'bc' calculates daily solar radiation based on daily temperature range using Bristow-Campbell model.

### Usage

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### Arguments

`days` |
Vector of class 'Date' of length n. |

`lat` |
Latitude in decimal degrees. |

`BCb` |
Bristow-Campbell model coefficient 'B'. |

`extraT` |
Optional. Vector of length n of extraterrestrial solar radiation [MJm-2]. If 'NULL' then it is calculated by the function. Providing extraterrestrial solar radiation speeds up the computation |

`Tmax` |
Vector of length n containing daily maximum temperature [C]. |

`Tmin` |
Vector of length n containing daily minumum temperature [C]. |

`BCc` |
Bristow-Campbell model coefficient 'C' usually equaled to 2. |

`tal` |
Clear sky transmissivity. |

### Details

Bristow and Campbell proposed a method for estimating solar radiation from air temperature measurements. They developed an empirical relationship to express the daily total atmospheric transmittance as a function of daily range in air temperature.

### Value

Vector of length n of daily solar radiation [MJm-2].

### Note

'Tmax', 'Tmin' can contain NA's, but length of vectors 'Tmax', 'Tmin' and 'days' has to be the same.

### Author(s)

Jedrzej S. Bojanowski

### References

Bristow, K.L., Campbell, G.S. 1984. On the relationship between incoming solar radiation and daily maximum and minimum temperature. Agriculture and Forest Meteorology, 31:159-166.

### See Also

'bccal' to calibrate model using reference data, 'bcauto' to perform auto-calibration, and 'ha' to use Hargreaves model to calculate solar radiation based on temperature range.

### Examples

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