Category Archives: Remote Sensing

Another Record-setting Year for Global Temperature

Peter Lobner

The National Aeronautics and Space Administration’s (NASA) Goddard Institute for Space Studies (GISS) released the results of an analysis by NASA and National Oceanic and Atmospheric Administration (NOAA) that showed that globally-averaged temperature in 2015 was the highest since modern record keeping began in 1880. You can read the NOAA / NASA press release at the following link:

You can download a copy of the more detailed NOAA / NASA briefing at the following link:

The analysis shows that globally-averaged temperature in 2015 exceeded the previous mark set in 2014 by 0.23 degrees Fahrenheit (0.13 degrees Celsius) and continued a warming trend, as shown in the following graph.

gistemp_graph_2015Source: NASA Goddard

In this graph, the zero on the y-axis is the average temperature for a 30-year period from 1951 to 1980. The trend lines show results for El Niño years (orange), La Niña years (blue), and all years (dashed line). The 2015 globally-averaged temperature was:

  • 57° F (0.87° C) above the 1951 to 1980 30-year (baseline) average, and
  • 62° F (0.90° C) above the 1901 to 2000 100-year (20th century) average

The distribution of global temperatures relative to the 1951 – 80 baseline is shown in the following charts.

NOAA:NASA briefing_1_Jan2016

NOAA:NASA briefing_2_Jan2016Source, both graphics: NOAA / NASA Annual Global Analysis for 2015

The NOAA / NASA press release cited above includes an animation that helps visualize Earth’s long-term warming trend based on data from 1880 to 2015. NOAA / NASA note that phenomena such as El Niño or La Niña, which warm or cool the tropical Pacific Ocean, can contribute to short-term variations in global average temperature. A warming El Niño was in effect for most of 2015

The full 2015 surface temperature data set and the complete methodology used by NOAA / NASA in their analysis are available to the public on the GISS Surface Temperature Analysis (GISTEMP) webpage at the following link:

The availability of the data and the analytical methodology allows the NOAA / NASA results to be subject to independent scrutiny. I commend NOAA and NASA for their openness in this matter, which will aid in reaching scientific consensus on the NOAA / NASA results.

This behavior by NOAA / NASA is a stark contrast to the United Nations (UN) Intergovernmental Panel on Climate Change (IPCC), which has failed to provide full public access to their underlying data and analytical methodologies and has been criticized for failing to rigorously apply the scientific method in their work. To help understand why the IPCC claim of “scientific consensus” is without merit, the Nongovernmental International Panel on Climate Change (NIPCC) published the book, “Why Scientists Disagree About Global Warming,” on 30 November 2015. You can download this document for free at the following link:

To help put this in perspective, I thank cartoonist Wiley Miller for the following timely and insightful cartoon published on 20 January 2016. I challenge you to apply this cartoon to your understanding of the climate change debate.

Cartoon Science_Jan2016Source: San Diego Union Tribune

U.S. Drought Indicators Derived From GRACE Satellite Data

Peter Lobner

Scientists at NASA’s Goddard Space Flight Center generate groundwater and soil moisture drought indicators each week. They are based on terrestrial water storage observations derived from GRACE satellite data and integrated with other observations, using a sophisticated numerical model of land surface water and energy processes. You can see current results for the continental U.S. at the following link to the National Drought Mitigation Center (NMDC), University of Nebraska-Lincoln, website:

Drought indicator maps for 6 July 2015 are reproduced below for:

  • Surface soil moisture
  • Root zone soil moisture
  • Shallow groundwater

The drought in the U.S. West looks most severe in the shallow groundwater map.

You can find information on the twin GRACE (Gravity Recovery and Climate Experiment) satellites at the following link:




What Satellite Data Tell Us About the Earthquake in Nepal

Peter Lobner

A 7.8 magnitude earthquake occurred in the Gorkha region of Nepal on 29 April 2015. A ground displacement map based on data gathered from the Sentinel-1A satellite is shown below. In this image, yellow areas represent uplift and the blue areas represent subsidence.

image Source: ESA

Surface ruptures are places in the ground where the quake has cracked the rock all the way up to the surface. Preliminary satellite data indicate that the Nepal earthquake did not cause any new surface ruptures.

Interferometric analysis of before and after satellite data can be used to measure more subtle changes in the vertical height of the ground along the fault line. Preliminary results from an interferometric analysis by the European Space Agency (ESA), generated from satellite scans of Nepal from April 17 and 29, 2015, is shown in the following image.

image  Source: ESA

Each fringe of color represents 2.8 cm of ground deformation. Areas immediately south of the fault line, like Kathmandu, sank more than a meter into the ground as a result of the quake. Directly north of the fault slip, further into the Himalayas, the ground was lifted up by about a half meter, indicated by the yellow in the first image, above.

Imagine the difficulty of gathering such data from direct physical examination of the affected area.

Read the full article on the Nepal earthquake preliminary satellite data analysis at the following link:

Read a general article on the use of satellite data to map earthquakes at the following link:

Where on Earth Does Lightning Flash Most?

Peter Lobner

According to satellite observations summarized in the following map, lightning occurs more often over land than over the oceans and more often closer to the equator.

image   Source: NASA

The map above shows the average yearly counts of lightning flashes per square kilometer from 1995 to 2013. The map was created using data collected from 1998–2013 by the Lightning Imaging Sensor (LIS) on NASA’s Tropical Rainfall Measuring Mission satellite, and from 1995–2000 by the Optical Transient Detector (OTD) on the OrbView 1/Microlab satellite. Flashes above 38 degrees North were observed by OTD only, as the satellite flew to higher latitudes.

Areas with the fewest number of flashes each year are gray or purple; areas with the largest number of lightning flashes—as many as 150 per year per square kilometer—are bright pink.  Be careful where you pitch your tent if you go on safari in central Africa.

Check out the story at the following link:

First Global Precipitation Map from NASA’s Global Precipitation Measurement Core Observatory

Peter Lobner
The Global Precipitation Measurement (GPM) Core Observatory – an initiative launched in 2014 as a collaboration between NASA and the Japan Aerospace Exploration Agency (JAXA) – acts as the standard to unify precipitation measurements from a network of 12 satellites. The result is NASA’s integrated multi-satellite retrievals for the GPM data product, called IMERG, which combines all of these data from 12 satellites into a single, seamless map.  An example of this global map is shown below:
Global precipitation map

Check out the short article and watch a short video showing the synthesized global precipitation map in action at the following NASA link:

More details on GMP mission can be found at the following NASA website: