As a result of his scientific work in Peru, Ulloa published Relación histórica del viaje á la América Meridional (Madrid, 1784), which contains a full, accurate, and clear description of the greater part of South America geographically, and of its inhabitants and natural history. (
It was published in English in 1806.)

In collaboration with Jorge Juan mentioned above, he also wrote Noticias secretas de América, giving valuable information regarding the early religious orders in Spanish America.
This work was published by David Barry in London, 1826.

Ulloa is the namesake for the meteorological term "Ulloa's halo" (also known as "Bouguer's halo"), which an observer may see infrequently in fog when the sun breaks through (for example, on a mountain) — effectively a "fog-bow" (as opposed to a "rain-bow").
 A fog-bow is defined as "an infrequently observed meteorological phenomenon; a faint white, circular arc or complete ring of light that has a radius of 39 degrees and is centered on the antisolar point.
When observed, it is usually in the form of a separate outer ring around an anticorona."
As a result of his scientific work in Peru, Ulloa published Relación histórica del viaje á la América Meridional (Madrid, 1784), which contains a full, accurate, and clear description of the greater part of South America geographically, and of its inhabitants and natural history. (It was published in English in 1806.)
In collaboration with Jorge Juan mentioned above, he also wrote Noticias secretas de América, giving valuable information regarding the early religious orders in Spanish America. This work was published by David Barry in London, 1826.
Ulloa is the namesake for the meteorological term "Ulloa's halo" (also known as "Bouguer's halo"), which an observer may see infrequently in fog when the sun breaks through (for example, on a mountain) — effectively a "fog-bow" (as opposed to a "rain-bow").  A fog-bow is defined as "an infrequently observed meteorological phenomenon; a faint white, circular arc or complete ring of light that has a radius of 39 degrees and is centered on the antisolar point. When observed, it is usually in the form of a separate outer ring around an anticorona."
Antonio de Ulloa