## What Trend?

Explore trends in meteorological data over different periods in recent history (1900 onwards)..

rainfall, temperature, solar radiation

**What Trend?** Is designed to allows you to visually explore trends in selected weather variables.

A line of best fit (least sum of squares) is shown, along with an estimate of whether the slope of the line is statistically different from zero (i.e. no trend).

Note: This is a simple, visual analysis. The data length is relatively short, and most weather parameters are typically highly variable, making trend analysis difficult.

### It allows decision-makers to answer questions such as:

**What Trend?** Allows you to explore a number of questions such as:

- Is the weather changing here?
- Am I getting more or less rain compared to the long term?
- Is there a trend in rainfall or temperature?

### Inputs

**What Trend?** *asks the user for:*

- The variable of interest
- Annual rainfall (mm)
- Annual average maximum temperature
- Annual average minimum temperature (0C)
- Accumulated solar radiation
- Incidences of: rainfall, maximum temperature, minimum temperature and solar radiation

When Incidences is selected, choose “greater than” or “less than” , value of parameter and duration of “incidence”

### Outputs

**What Trend?** plots time series of selected variables: rainfall, temperature, radiation and incidences of specified occurrences. A simple line of best fit (least sum of squares) is provided along with an estimate of whether the slope of the line is significantly different from zero (i.e. no trend).

A graph of annual differences from the mean and cumulative differences (residual mass curves) provide another view of departures from the mean over the duration of available (or selected) data.

### History

**What Trend?** Is a new analysis for Australian CliMate and is provided to allow you to explore whether there are visually observable trends in a specified variable (your judgment)?

Given the importance of climate change in public debate, **What Trend? **aims to empower the user to explore and discover for their location and variable whether there is are apparent trends.

### References