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Table 1 Definition of the climatic variables

From: Quantifying the role of weather on seasonal influenza

Climatic variable

Formula

Average temperature

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations} average\ daily\ temperature\left(j,s\right)}} \)

Daily variation of temperature

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations}\left( \max daily\ temperature\left(j,s\right)- \min daily temperature\left(j,s\right)\right)}} \)

Relative weekly variation of temperature

Average temperature(week t + 1) − Average temperature(week t )

Absolute weekly variation of temperature

|Average temperature(week t + 1) − Average temperature(week t )|

Average relative humidity

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations} average\ daily\ relative\ humidity\left(j,s\right)}} \)

Daily variation of relative humidity

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations}\left( \max daily\ relative\ humidity\left(j,s\right)- \min daily\ relative\ humidity\left(j,s\right)\right)}} \)

Relative weekly variation of relative humidity

Average relative humidity(week t + 1) − Average relative humidity(week t )

Absolute weekly variation of relative humidity

|Average relative humidity(week t + 1) − Average relative humidity(week t )|

Average absolute humidity

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations} average\ daily\ absolute\ humidity\left(j,s\right)}} \)

Daily variation of absolute humidity

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations}\left( \max daily\ absolute\ humidity\left(j,s\right)- \min daily\ absolute\ humidity\left(j,s\right)\right)}} \)

Relative weekly variation of absolute humidity

Average absolute humidity(week t + 1) − Average absolute humidity(week t )

Absolute weekly variation of absolute humidity

|Average absolute humidity(week t + 1) − Average absolute humidity(week t )|

Average wing speed

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days}{\displaystyle {\sum}_{s=0}^{stations} average\ daily\ wind\ speed\left(j,s\right)}} \)

Rainfall height

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days} average\ daily\ rainfalls\ height\left(j,s\right)} \)

Sunshine duration

\( \frac{1}{days}\cdot \frac{1}{stations}\cdot {\displaystyle {\sum}_{j=0}^{days} average\ daily\ sunshine\ duration\left(j,s\right)} \)