01 · DATA SOURCE
NASA POWER
TerraTrend retrieves historical monthly Earth-system estimates from NASA POWER for the coordinates and period selected.
These are gridded data products, not measurements from a weather station at the exact selected point.
The planet
leaves clues.
We follow the data.
Explore long-term changes in Earth-system conditions using NASA POWER data, transparent statistical methods, and location-based analysis.
✦ Evidence-led environmental analysis NASA POWER data
EARTH SYSTEM / MONITORING TERRA / 001
24.9° N 91.9° E
5 indicatorsONE EARTH
01 / OBSERVERetrieve the data
02 / DETECTMeasure the trend
03 / EXPLAINFollow the evidence
FOLLOW THE SIGNAL✧NASA POWER DATA✧OPEN, EXPLAINABLE METHODS✧GLOBAL LOCATIONS✧REPRODUCIBLE RESULTS
01 / FIELD LABORATORY
Begin an investigation.
Choose a place and an Earth system indicator. We'll do the scientific detective work.
GEOSPATIAL VIEW
Choose your point on Earth
● INTERACTIVE MAP
Sylhet, Bangladesh
24.89° N / 91.87° ETHE EVIDENCE
Decades of change
AWAITING DATA
⌁
Explore the evidence.Select your parameters, then analyze NASA data.NASA annual dataOLS trend line—
TREND / DECADE—Awaiting analysis
ESTIMATED TOTAL CHANGE—Across the study period
STATISTICAL TEST—p-value at α = 0.05
YEARS ANALYZED—Complete calendar years
THE DETECTIVE'S REPORT
A story written in evidence.
Your findings will appear here after retrieving and analyzing authentic NASA POWER data. Each conclusion includes its study period, trend, and statistical uncertainty.
MEASUREMENT NOTES
No result is interpreted until the source data is retrieved. We never substitute fabricated numbers for NASA data.
Read source methodology ↗02 / TWO PLACES, TWO STORIES
Same planet. Different signals.
Compare two regions under the same indicator and time window. Do they tell the same story?
VS
PARALLEL EVIDENCE
AWAITING COMPARISONHow do the trends compare?
↗↘
Two locations. One scientific question.Select two places to compare their trends.LOCATION A—
Awaiting NASA data
LOCATION B—
Awaiting NASA data
Both places are analyzed using the same variable, period and regression method.
Source requests: Location A data ↗ · Location B data ↗
03 / UNDERSTANDING THE DATA
Understand every clue.
Learn how the data are prepared, analyzed, and interpreted.
02 · PICK THE PLACE
Where on Earth?
Choose a city from the list or click the world map. Latitude and longitude are simply the north/south and east/west numbers that identify that spot.
03 · PICK WHAT TO MEASURE
Which Earth indicator?
Temperature = how warm the air is. Precipitation = how much rain falls. Humidity = moisture in air. Wind speed = how fast air moves. Solar energy = sunlight energy reaching the surface.
04 · PICK THE YEARS
When did change occur?
Select the first and last calendar years, then click Analyze NASA data. Only complete years with all 12 monthly records are included.
05 · READ THE GRAPH
How did it change?
The chart line connects values for successive years. The dashed trend line estimates the overall long-term direction. Hover over or focus a point to see its year and value. A zigzag does not always mean a long-term trend.
06 · READ THE FINDINGS
What do the numbers say?
Trend per decade = estimated change in ten years. Estimated change = change along the fitted line across the period. Significance tests evidence that the linear slope differs from zero. Years analyzed counts usable complete years.
07 · COMPARE TWO PLACES
Could trends differ?
Under Compare, choose two cities and click Compare evidence. You will see two series for the same years and indicator. Their slopes may differ, but the tool does not statistically test the difference between the slopes.
08 · SAVE OR SHARE
Keep your evidence
CSV downloads annual values for further analysis; Copy findings copies the interpretation; Print / save PDF creates a printable report with the source and methods.
HOW TO INTERPRET A RESULT
Read the direction and rate
A positive slope indicates an estimated increase; a negative slope indicates an estimated decrease. The rate per decade describes the fitted change over ten years.
What does “p-value” mean?
A p-value below 0.05 is commonly called statistically significant under the model assumptions. It is not proof of what caused the change and does not guarantee the trend will continue. The confidence interval shows the uncertainty in the estimated slope.
Ready?Select a location and indicator, choose a study period, then analyze NASA POWER data.Go to the explorer ↗
04 / THE SCIENCE BEHIND THE SIGNAL
Beautiful charts.
Defensible conclusions.
Nothing hidden. Understand exactly how each Terra Trend conclusion is made.
Ask the Earth
We query NASA POWER's monthly point API for historical Earth-system estimates at the selected coordinates. Each chart traces back to its source request.
Respect the units
We calculate day-weighted annual means for temperature and other rates, and annual totals for precipitation. Years missing a month are excluded.
Find the trend
Ordinary least squares estimates the annual slope. A two-sided t-test, p-value, and 95% confidence interval describe statistical evidence.
Tell it responsibly
We report effect size, uncertainty, and caveats. Statistical significance is not causation, and a non-significant result does not prove stability.
WHY THIS MATTERS
One planet. More than one interpretation.
NASA POWER is a gridded Earth science data product, not a thermometer physically installed at your exact selected point. Meteorological data combine measurements and models. Regional differences, missing months, and year-to-year dependence affect how conclusions should be read.
LINEAR TREND
y = α + β × yearβ is the change per year. Multiply by 10 to obtain the estimated change per decade.STATISTICAL EVIDENCE
p < 0.05Conventional threshold for a two-sided regression slope test; assumes independent errors. See limitations before interpretation.Trace the evidence.
NASA POWER monthly API ↗Original documentation and datasets, linked directly.