diff --git a/radolan.go b/radolan.go
index 19ffff1be7f63bd9a6373a59fe7aa614a312c6b7..7b88b3e6b0b8373ae64935b10047bbe9de728f90 100644
--- a/radolan.go
+++ b/radolan.go
@@ -21,7 +21,7 @@ package radolan
 import (
 	"archive/tar"
 	"bufio"
-	"compress/gzip"
+	"compress/bzip2"
 	"fmt"
 	"io"
 	"sort"
@@ -132,16 +132,12 @@ func NewComposite(rd io.Reader) (comp *Composite, err error) {
 	return
 }
 
-// NewComposites reads tar gz data from rd and returns the parsed composites sorted by
+// NewComposites reads .tar.bz2 data from rd and returns the parsed composites sorted by
 // ForecastTime in ascending order.
 func NewComposites(rd io.Reader) ([]*Composite, error) {
-	gzipReader, err := gzip.NewReader(rd)
-	if err != nil {
-		return nil, err
-	}
-	defer gzipReader.Close()
+	bzipReader := bzip2.NewReader(rd)
 
-	tarReader := tar.NewReader(gzipReader)
+	tarReader := tar.NewReader(bzipReader)
 
 	var cs []*Composite
 	for {